How to screen SARS-CoV-2 peptides to facilitate T cell research

Posted by Yuri Poluektov on Aug 17, 2020 12:00:00 PM

Whenever our immune system is faced with a challenge, be it a multicellular parasite, a bacteria, a virus, or even cancer, this threat is detected and sampled primarily by the protein sequence of the pathogen in question. Other aspects of the pathogen, such as its glycosylation pattern or the peculiar structures of its RNA and DNA molecules could have a strong effect on how the immune system deals with it. But, overall, the adaptive aspect of the mammalian immune system has evolved over many years to examine the protein sequences that make up the invading pathogen. The key function of our immune system relies on its ability to constantly sample all proteins present in our body and determine whether it is a protein that belongs or a protein that must be eradicated together with any cells or organisms that produce it. Unfortunately, most proteins are too large for the immune system to sample at once and so it has developed a mechanism to cut the full-length proteins into small stretches of amino acids which are examined individually.

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Topics: Tetramer, QuickSwitch, covid-19, SARS-CoV-2

MuLV gp70 (AH1) Tetramer - a great tool for observing antigen specific immune response in cancer

Posted by M. Mamunur Rahman, PhD on Jun 25, 2020 12:00:00 PM

MuLV gp 70, also designated as AH1 (SPSYVYHQF), is an endogenous viral envelope glycoprotein encoded in the mouse genome that is transcriptionally silent in normal tissues. The expression of gp70 is reactivated in a few cancer cell lines including CT26 colorectal cancer and B16 melanoma cells. Other investigators have demonstrated the presence of MuLV-encoded molecules in murine lymphomas and leukemias as well as Simian Virus 40 (SV40)-transformed NIH-3T3 cells. Researchers measure total T cell and T cell subset by detection of various cell surface molecules to gain better insight into the central role of the immune system. MBL International offers MHC tetramer reagents for murine model antigens, tumor antigens, viral antigens, etc. MHC-peptide tetramer complexes detect antigen specific T-cells at the single cell level, allowing for accurate measurements of the functional immune response in cancer, infectious diseases, and automimmune diseases.

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Topics: Tetramer

Intracellular Staining with MHC Tetramers

Posted by Dennie Magcase on May 27, 2020 1:00:00 PM

T-cells recognize peptides/MHC complexes (pMHC) through the T-cell receptor (TCR). This is the first step for the initiation and shaping of protective immunity against viruses and tumor antigens. Fluorescently labelled pMHC tetramers have dramatically transformed the detection of antigen specific T-cells. MHC tetramer staining of antigen specific T cell clonotypes is detected by flow cytometry to probe T-cell responses1 and to further characterize antigen-specific T cells, for example, to study the surface markers as well as intracellular proteins. The measurement and analysis of effector function of antigen-reactivated T cells is now possible by MHC tetramer and flow cytometry-based intracellular cytokine staining (ICS). This method allows concurrent phenotypic characterization and cytokine detection within single cells2.

The production of cytokines plays an important role in immune response.  Cytokines are involved in many pathways, including the induction of many anti-viral proteins by IFNγ, the induction of T cell proliferation by IL-2, and the inhibition of viral gene expression and replication by TNFα3.  Cytokines are not preformed factors but are produced and secreted in response to cellular activation.

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Topics: Tetramer, cytokine

In vivo NIRF whole-body imaging through MHC tetramers

Posted by Yuri Poluektov on Apr 8, 2020 1:00:00 PM

The use of MHC tetramers for the detection of antigen specific T cells has been a well-established technique since it originally gained prominence in the mid-1990s. Since then, the sophistication of MHC tetramer and multimer design as well as its sensitivity in detecting target T cells has been steadily improving. Most applications of MHC Tetramers involve the use of Flow Cytometry to enumerate, purify or sort specific T cells, but in some cases, it is possible to use tetramers to visualize entire immunological processes taking place inside a whole body.

We want to bring to your attention a recent paper by Welsh and Song et. al. (Plos Biology Feb, 2020)1. In their study, while constantly using MHC Class II tetramers to detect and enumerate pathogenic T cells, responsible for the progression of Rheumatoid Arthritis (RA) as well as Experimental Autoimmune Encephalomyelitis (EAE) induced in mice models, the group performed a number of imaging trials. This imaging procedure involved a modified in vivo NIRF whole-body imaging technique described in the paper. The group was successful in identifying a co-localized population of Collagen peptide specific T-cells and a molecular probe specific for denatured Collagen protein molecules using an IRDye800CW-conjugated CII(280–294) peptide loaded HLA-DR1 tetramer.

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Topics: Tetramer, QuickSwitch

Why Smart-IP is the smart way to IP

Posted by Bindi M. Doshi, PhD on Mar 26, 2020 1:00:00 PM

You have been given the mission to start a new project. A tiny tube is put in your hands and you’re told it contains a potentially interesting protein and your job is to characterize it. After you wipe nervous sweat from your brow, you get down to business. Step one- how to isolate your new buddy? Immunoprecipitation can help with this question! You determine which epitope tag is on your protein and go to to see what you can buy to help this new adventure. You see there are antibodies conjugated to magnetic beads, which help protein pull downs from cell lysates. It's easy, it's fast.  Hmmmm- promising.

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Topics: Epitope Tag

Screening for COVID-19 T-cell peptides and immune monitoring with MHC tetramers in a single assay

Posted by Pirouz Daftarian, Ph.D., Marc Delcommenne, Ph.D. on Mar 17, 2020 3:00:00 AM

COVID-19 infected cells can be recognized by T-cells only after SARS-CoV-2 peptides are processed and presented in the context of self MHCs.

Identifying these peptides have essential utilities:

  • Immune monitoring: Using peptide-MHC tetramers to assess vaccine-induced immunity
  • Designing potent vaccines that elicit durable responses
T-cells are activated only by interacting with processed peptides (e.g. of SARS-CoV-2) that sit in the groove of MHC Class I and II molecules. Identifying these peptides can be used (in forms of peptide-MHC tetramers) to assess vaccine induced immunity and assist in designing potent vaccines with durable responses.
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Topics: Tetramer, Peptide, covid-19, SARS-CoV-2, vaccine, MHC

Cancer Immunotherapy - Growing focus on CD4+ T lymphocytes and MHC Class II Neoantigens

Posted by Anthony G Pietrantoni on Feb 11, 2020 1:00:00 PM

It is now well accepted that CD8+ T cells play a central role in mediating anti-tumor immunity by recognizing tumor-associated antigens presented on major histocompatibility complex class I by their expressed T cell receptor.  Majority of studies on cancer neoantigens have therefore focused on MHC class I restricted antigens recognized by CD8+ T cells.   However it is also becoming increasingly clear that CD8+ T cell binding neoantigens are not sufficient for mounting a powerful anti tumor response. The recent paper by Alspach et al. proved that spontaneous and immunotherapy-induced antitumor responses required presence of CD4+ in addition to CD8+ T cells (1).

Multiple studies indicate that CD4+ T cells mediate antitumor effects through mechanisms that vary according to tumor environments whether they act as helper or cytotoxic cells but are ultimately dependent on MHC class II neoantigens.   In some instances CD4+ T cells were shown to acquire cytotoxicity activity in vivo in presence of a high level of IL-2 or when IL-2 sequestering T Reg cells were absent (2).  A recent investigation reported that cytotoxic CD4+ T cells are particularly abundant among supercentenarians and reached 25% of T cells on average, suggesting they are essential to protect against infections and cancers, contributing to achieve an extended disease-free life expectancy (3).  Therefore, with improved understanding of the intricate interactions between cytotoxic and helper CD4+ lymphocytes with tumors and antigen presenting cells, interest is currently focused on MHC class II dependent immune activation mechanisms.  MHC class II restricted neoantigens have now the potential to be promising targets of cancer immunotherapies.

Learn more about Class II Tetramers



(1)Alspach, E. et al. MHC-II neoantigens shape tumour immunity and response to immunotherapy. Nature 574: 696–701 (2019).

(2) Śledzińska, A. et al. Regulatory T Cells Restrain Interleukin-2- and Blimp-1-Dependent Acquisition of Cytotoxic Function by CD4+ T Cells. Immunity. 52(1):151-166 (2020).

(3) Hashimoto K. et al. Single-cell transcriptomics reveals expansion of cytotoxic CD4 T cells in supercentenarians. Proc Natl Acad Sci USA. 116(48):24242-24251 (2019).

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Topics: Tetramer, Cancer

Is your drug candidate able to reverse the T Cell Exhaustion-like state in our in vitro functional screening assay?

Posted by Pirouz Daftarian, Ph.D. on Dec 12, 2019 1:00:00 PM

The goal of cancer immune checkpoint therapies is to cure tumor-specific T cells from dysfunction which is caused by elements from tumor deposits.  In this blog, we briefly describe the process of T cell exhaustion and how it can be harnessed for immuno-oncology drug discovery and more specifically to screen immune checkpoint drug candidates. First, the current function-based characterization methods for immunomodulatory drug candidates will be summarized. We have selected three methods which mimic prerequisite parameters of early T cell exhaustion (TEX). Next, we briefly describe an improved recall antigen-based potency assay as detailed elsewhere. Lastly, we describe an in vitro reversible early TEX-like  model, which may be tailored with cancer-induced T cell suppression agents.  Here it should be noted that cancer induced T cell dysfunction is also referred to as TEX, covering a broad spectrum of different molecular T cell pathologies. The term “T cell exhaustion” in this review mainly refers to an early stage of this process.  We have devised an in vitro model that recapitulates components of tumor deposits responsible for inducing TEX.

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Topics: Tetramer, Cancer, t cell

Blocking Fc receptors for flow cytometry

Posted by Wushouer Ouerkaxi, Ph.D. on Oct 17, 2019 1:00:00 PM

While, in theory, using antibodies against Fc Receptors (FcRs) is the best way to eliminate unwanted signals mediated by FcR binding, you may not always have a well-optimized antibody pool against FcRs sitting right in front of you for your experiment. Furthermore, such a blocker may not be applicable when you have one of the FcRs, such as CD16, CD32 or CD64 to measure in your channel. In this blog, we share an "old school" way of blocking by just using a serum that is routinely available in most labs.

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Topics: Antibodies, Fc blocker

New tetramer for vaccine research targeting Tuberculosis and Ag85B specific T-cells

Posted by Bindi M. Doshi, PhD on Jul 23, 2019 1:00:00 PM

Tuberculosis (TB) is caused by the Mycobacterium tuberculosis and usually targets the lungs.  This disease is spread when an infected person sneezes or coughs, thereby releasing small droplets into the air and passing to a new individual. When left untreated, death can occur. Thankfully, there is a vaccine for TB called Bacille Calmette-Gurin (BCG) and is often given to young children.  This vaccine has been shown to last 15 years. There is some doubt about the efficacy of the BCG vaccine in adult pulmonary TB1,2.  For this reason, more research needs to be done to provide a safe and effective TB vaccine for adults.

Antigen (Ag) 85 is gaining interest among vaccine development research.  Ag85 is preserved in Mycobacterium and allows bacteria to evade the host immune response by preventing mechanisms involved in terminating the infection3.  Research continues to uncover exactly how Mycobacterium tuberculosis persists and remains in an infected person while evading the immune system.  New advances in immunology are giving researchers a greater picture for how the immune response is manipulated by this bacteria.  It is clear that with greater understanding of how the human immune response system functions and how different infections manipulate this system, that targeted therapies, including vaccines, can be developed to combat the infection successfully.

MBL International is pleased to announce the launch of our new tetramer targeted to Ag85B-specific T cells for murine studies. As always, our team is on hand for any question or request that you may have.

Product Code Target Conjugate
TS-M719-1 I-Ab Mtb Ag85B240-254 Tetramer-FQDAYNAAGGHNAVF PE
TS-M719-2 I-Ab Mtb Ag85B240-254 Tetramer-FQDAYNAAGGHNAVF APC

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(1) Davenne,T., & McShane, H. (2016). Why don't we have an effective tuberculosis vaccine yet?. Expert review of vaccines15(8), 1009–1013. doi:10.1586/14760584.2016.1170599

(2) Andersen, P., & Doherty, T.M. (2005). The success and failure of BCG - implications for a novel tuberculosis vaccine. Nature Reviews Microbiology,3(8), 656-662. doi:10.1038/nrmicro1211

(3) Babaki, M. K., Soleimanpour, S., & Rezaee, S. A. (2017). Antigen 85 complex as a powerful Mycobacterium tuberculosis immunogene: Biology, immune-pathogenicity, applications in diagnosis, and vaccine design. Microbial Pathogenesis, 112, 20-29. doi:10.1016/j.micpath.2017.08.040

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Topics: Tetramer, Immunology, tuberculosis

Why protein phosphorylation is crucial in disease research

Posted by Bindi M. Doshi, PhD on Jun 13, 2019 1:00:00 PM

Protein phosphorylation is quintessential for specific pathways to function.  This function can be influenced by internal or external factors.  It is a reversible action with the involvement of kinases and phosphatases1.  This activity is crucial in the cell cycle, apoptosis, and signal transduction pathways.  If a protein is phosphorylated or dephosphorylated when it shouldn’t be, there can be severe disruptions to the cellular pathway.  At times, the phosphorylation state can be the cause of a disease.  This has been found in degenerative diseases, cancers, and various pathways involving the immune system2.  For instance, kinase inhibitors have been successful in cancer treatments. 

Enzymes control phosphorylation.  Kinases function to add phosphate groups to proteins and phosphatases function to remove phosphates.  Typically, phosphorylation occurs on serine, threonine, or tyrosine residues. This process can be very quick or it can take many hours. It results in a conformational change which either activates or inactivates protein activity.

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Topics: Antibodies, phosphorylation, pathways, kinases

QuickSwitch, a tool for adoptive T cell transfer

Posted by Yuri Poluektov on Apr 24, 2019 1:00:00 PM

Our understanding of how the immune system responds to cancer has increased by leaps and bounds in the past two decades, allowing us to develop a new approach to fight cancer that uses the power of the body’s own immune system to prevent, target, control, and eliminate the disease. Collectively, this technique of battling cancer is known as cancer immunotherapy. Such an approach encompasses many methods from broad ones like applying immune checkpoint blockers (ICB) or using monoclonal antibodies (mAbs) that target known cancer antigens to more personalized ones like adoptive T cell transfer including the use of Chimeric antigen receptor (CAR) T cells.

It is this personalized immunotherapy approach that has sparked a great deal of interest among researchers. This method involves the extraction of a patient’s T cells and the subsequent stimulation of the rare T cells populations that can fight cancer with specific antigens. For this form of therapy to work there needs to be an exact knowledge of the peptide sequences derived from tumor cells (neo-epitopes) that can be used to artificially stimulate a patient’s T cells to fight them.

Previously, we have described how by using the QuickSwitchTM Quant Platform peptides, they can be tested for their ability to bind MHC Class I molecules. This test does not involve prediction algorithms or large swaths of data with a great deal of false positives but provides an in vitro result of whether or not the peptide can be presented on the MHC molecule in about 8 hours. It is our hope that by using our kit, researchers will be able to discover and validate neoantigen peptide sequences more effectively, which would open up new ways for adoptive T cell transfer in cancer immunotherapy.

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Topics: Tetramer, QuickSwitch

Stabilizing cellular antigens the easy way using Transfix

Posted by Anthony G Pietrantoni on Mar 29, 2019 1:00:00 PM

Many researchers and clinicians have issues with keeping their whole blood or CSF samples viable over time. Whether the reason is because the collection occurred on a Friday afternoon with no lab analysis available until Monday, or collecting a large batch of samples to send out to the lab at the other end or the state, cellular degradation can be a problem. Don’t let this happen to you.

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Topics: FCM, TransFix, Preservation, Cell Stabilization

Is Wnt3a an essential component in organoid culture?

Posted by M. Mamunur Rahman, PhD on Mar 27, 2019 2:00:00 PM

Organoids are self-organized three-dimensional tissue cultures that are derived from mammalian pluripotent or adult stem cells. These in-vitro-grown cell clusters are given possibilities to replicate much of the complexity of an organ. There are potentially as many types of organoids as there are different tissues and organs. To date, researchers have been able to prepare brain, kidney, lung, intestine, stomach, liver and many more are developing.

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Topics: 3D Cell Culture, NCP, organoid

3D cell imaging made easier

Posted by Bindi M. Doshi, PhD on Jan 29, 2019 1:00:00 PM

There is an increase in demand for scientists to show cell migration and proliferation on a surface that more closely mimics an in vivo environment.  Using a gel surface can be tricky.  Therefore, MBL has a unique and innovative technology where a proprietary plastic film is used for plating cells.  This technology is easy to use with many different cell types and is reproducible every time.  Please see the table below comparing various techniques for 3D cell cultures:

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Topics: 3D Cell Culture, NCP

LC3: The gold standard for autophagy research

Posted by Lise Peeters, PhD on Dec 13, 2018 1:00:00 PM

LC3, a mammalian homologue of yeast ATG8, is a soluble protein that is distributed ubiquitously in mammalian tissues and cultured cells. LC3 has been studied most extensively and is frequently used as an autophagy marker in mammals.  Newly translated LC3 (proLC3) is immediately processed at the C-terminus in order to form LC3-I. During autophagy, autophagosomes engulf cytoplasmic components, including cytosolic proteins and organelles. Concomitantly, a cytosolic form of LC3 (LC3-I) is conjugated to phosphatidylethanolamine to form LC3-phosphatidylethanolamine conjugate (LC3-II), which is recruited to autophagosomal membranes.

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Topics: Autophagy, LC3, atg8

Gating strategy for tetramer analysis to eliminate non-specific event

Posted by Wushouer Ouerkaxi, PhD, MD on Nov 14, 2018 1:00:00 PM

While MHC tetramer staining of antigen specific T cells for flow cytometry is considered highly specific, it could still be associated with non-specific staining. The gating strategy shown below is an example that investigators have used to reduce non-specific staining events using a dump channel. A dump channel can be planned on a case by case basis, on the experimental design, and consists of a pool of antibodies against cells that do not express our specific targets. For example, CD8+ T cells, anti-CD4/anti-CD14/anti-CD19 may be used to eliminate these immune cells from our targeted gate, and all may be labeled with the same fluorochrome. 

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Topics: Tetramer, Flow Cytometry

Shed a little light in your cells using anti-GFP

Posted by Bindi M. Doshi, PhD on Oct 24, 2018 1:02:00 PM

In 2008, the Nobel Prize in Chemistry was awarded to Dr. Roger Y. Tsien, Dr. Osamu Shimomura, and Dr. Martin Chalfie for their discovery and development of the green fluorescent protein (GFP).  Since then, fluorescent protein (FP) technology has made drastic advancements by many researchers.  FP antibodies are used in multiple applications.

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Topics: Antibodies, rfp, gfp

Which tetramers can be used for my mouse samples?

Posted by Tomohiro Nakajo on Aug 28, 2018 1:00:00 PM

The thymus shapes a host's T-cell repertoire so they do not respond to "self" antigens, yet are able to recognize "non-self" antigen challenges (from pathogens and tumors). T cell participation in these immune responses are dependent on interaction with peptide- and self-MHC. In other words, T cells only recognize the peptides derived from cancers or pathogens if they are embedded in the cleft of self host MHC grooves. Such peptides are processed and presented on the surface of antigen-presenting cells (MHC class I and II in dendritic cells, macrophages, and B cells) or all nucleated cells (MHC class I) allowing T cells to identify infected or cancer cells. Direct detection of such Ag-specific T cells and functional analysis is important for understanding disease immunopathogenesis and the process of drug development. MBL International has had tremendous success in advancing the methodologies to accurately measure antigen-specific T cells. 

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Topics: Tetramer

Learn why IL-18 is an exciting biomarker for various diseases

Posted by Tomohiro Nakajo on Jul 31, 2018 1:00:00 PM

As described in previous blog posts, our IL-18 related products are used widely among researchers around the world. IL-18 plays an important role in the cytokine network. Abnormal values of IL-18 are seen in various disease areas such as allergy or autoimmune diseases. 

In this blog, we discuss two diseases correlated with IL-18. Neither of them are allergy or autoimmune diseases, but very interesting nonetheless.

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Topics: IL-18, ELISA, pro IL-18

Improve your neutralization using monoclonal IL-18 antibodies

Posted by Tomohiro Nakajo on Jun 19, 2018 1:00:00 PM

Interleukin-18 (IL-18) is a member of the IL-1 superfamily and synthesized as an inactive precursor that requires processing by caspase-1 to become an active cytokine. IL-18 plays a major role in the production of interferon-γ (IFN-γ) from T cells and natural killer cells. Refresh your memory by reviewing a couple of previous blog posts.

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Topics: IL-18, ELISA, pro IL-18

Tips for successful results using our extremely popular IL-18 ELISA kits

Posted by Tomohiro Nakajo on May 30, 2018 1:00:00 PM

Interleukin-18 (IL-18) is a member of the IL-1 superfamily and synthesized as an inactive precursor requiring processing by caspase-1 into an active cytokine. IL-18 plays a major role in the production of interferon-γ (IFNγ) from T cells and natural killer cells. Refresh your memory by reviewing a couple of previous blog posts.

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Topics: IL-18, ELISA, pro IL-18

How do I even get started? Lessons for setting up your experiments

Posted by Bindi M. Doshi, PhD on Apr 26, 2018 1:00:00 PM

Biology can be daunting.  Experiments can be daunting.  Setting up your own biological experiments can be terrifying!  But it doesn’t need to be. 

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How to detect functional PCSK9 quickly and easily 

Posted by Bindi M. Doshi, PhD on Mar 30, 2018 2:45:00 PM

PCSK9 remains an important target in cholesterol research.  One of the hurdles in this research area is determining which PSCK9 form is present and binding with LDLR.  Our new Human PCSK9 Functional Assay Kit is designed to detect active PSCK9 binding with LDLR. 

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Topics: PCSK9, Metabolism, PCSK9 ELISA Kit

Can NanoCulture Plate (NCP) be a better 3D cell culture platform?

Posted by M. Mamunur Rahman, PhD on Mar 28, 2018 1:01:00 PM

Cell-based assays are the first step for drug screening applications and have been performed in monolayer culture condition for decades. These traditional cell cultures have been known to enhance integrin signals, which mask several biologic activities in tumor cells. In contrast, it is already known that 3D cell culture can replicate the intra-tumor microenvironment.

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Topics: 3D Cell Culture, NCP

Quick!  Switch out your peptide! 

Posted by Marc Delcommenne, PhD on Mar 27, 2018 12:58:00 PM

The immunotherapy field is making great progress in aiding many disease treatments.  The hope is that one day, personalized immunotherapy can be used so each patient can use their own immune system to overcome their specific disease affliction.  QuickSwitch is a tool for creating custom MHC class I tetramers quickly and easily.

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Topics: Tetramer, QuickSwitch, Peptide, Peptide Exchange

Antibodies for fluorescent proteins: Will it cross react with my variant?

Posted by Tomohiro Nakajo on Feb 27, 2018 1:00:00 PM

Green fluorescent protein (GFP) was first isolated by Dr. Osamu Shimomura in 1961. Since then, fluorescent protein (FP) technology has made drastic advancements by many researchers. Currently, FP technology is the most popular tool for visualizing target proteins. Dr. Shimomura, Martin Chalfie and Roger Y. Tsien won the 2008 Nobel Prize in Chemistry to mark their great achievements in life science research.

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Topics: Fluorescent Proteins, Antibodies

S100 Proteins: Study their Hundreds of Functions with MBL ELISA Kits

Posted by Tomohiro Nakajo on Jan 24, 2018 1:00:00 PM

Have you heard of the S100 protein family? S100 refers to proteins that are 100% soluble in saturated ammonium sulfate solution. They were first discovered as a major protein fraction (0.6% of total soluble proteins) isolated from bovine brain by B.W. Moore in 1965.

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Topics: ELISA, S100 Proteins

Mechanisms and detection methods of p62/SQSTM1 and its importance in the autophagy pathway.

Posted by Tomohiro Nakajo on Jan 9, 2018 10:24:11 AM

Mechanisms of Autophagy

The ubiquitin-conjugating protein p62/SQSTM1 is thought to be a scaffold protein that interacts with a variety of molecules involved in toll-like receptor (TLR) signaling, such as TRAF6, ERK, and aPKC. Recent evidence suggests that p62 binds directly to the autophagosome marker LC3 and is then selectively degraded by autophagy.

p62 contains multiple phosphorylation sites. Sequential phosphorylation of these sites regulates biological defense mechanisms such as selective autophagy and the Keap1-Nrf2 system. Therefore, the failure of the p62 pathway is associated with various diseases such as cancer and many neurodegenerative diseases.

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Topics: Autophagy, p62

Evaluating the biological activity of a cancer vaccine with the HLA-A*02:01 QuickSwitch™ Quant platform

Posted by Lise Peeters, PhD on Dec 11, 2017 11:33:12 AM

Immuno-oncology is a growing field in which different strategies such as immune modulators, vaccines and adoptive cell therapies are applied for new immunotherapies. Cancer vaccine immunogenicity and stability are two important parameters in vaccine development. In addition, vaccine immunogenicity implies accurate enumeration of antigen specific T-cells. MHC tetramers can help monitor peptide vaccine immunogenicity and stability.

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The problem with Ultracentrifugation for exosome isolation

Posted by Dennie Magcase on Nov 2, 2017 12:00:00 PM

Ultracentrifugation is regarded as the gold standard method for exosome isolation.  The ultracentrifugation process is time consuming and may introduce protein and nucleic acid contamination.  Pre-clearing samples by one or more low speed centrifugation steps will deplete the cells, platelets, and large apoptotic bodies.    Larger extracellular vesicles can be pelleted at forces between 10000-20000 x g.  Smaller extracellular vesicles can be pelleted at higher speeds, ranging from 100000-200000 x g. Depending on the protocol, it can take up to 24 hours to isolate exosomes by ultracentrifugation.  It is impossible to achieve absolute separation due to potential contamination of proteins and nucleic acids.

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Topics: Exosomes, ultracentrifugation

Protein analysis in circadian rhythm research

Posted by Tomohiro Nakajo on Sep 27, 2017 12:00:00 PM

Living organisms on the earth synchronize their activity to a 24 hour light and dark cycle generated by the rotation of the earth. This biological rhythm is called the circadian rhythm.

Recently the molecular mechanism for the oscillation of the circadian rhythm has been elucidated and the approximately 24-hour-rhythm was found to be generated by a transcription-translation feedback-loop of clock genes expressed by almost all cells. In particular, BMAL1, CLOCK, PERs and CRYs play key roles in oscillation of the circadian rhythm and rhythmically regulate the expression of downstream genes (hereinafter referred to as clock-controlled genes [CCGs]).

So far, the expression analysis of CCGs is mainly performed by mRNA quantification, like qRT-PCR and in situ hybridization. However, it is necessary to analyze protein expression level, post-translational modifications like phosphorylation, and ubiquitination for understanding the molecular mechanism of circadian rhythm. Actually, phosphorylation and ubiquitination of PER and ubiquitination of CRY are well known.

Why are these protein expression analyses not well done? The answer is very simple: because there weren't any good antibodies in this market, so we developed antibodies against CCGs.

At first we developed antibodies against PER1/2, CRY1/2, BMAL1 and CLOCK, playing core feedback loop in circadian rhythm. BMAL1 and CLOCK form a heterodimer, which binds to the regulatory region (E-box) in per1/2 and cry1/2 to positively regulate transcription. PER and CRY proteins then form a complex, migrate to the nucleus, and negatively regulate the function of the BMAL1/CLOCK complex. CCGs with E-box elements are expressed and are regulated by the BMAL1/CLOCK complex, and various genes are expressed according to circadian rhythm.

We successfully developed antibodies against all of the core feedback loop members. Anti-PER1, PER2, BMAL1 and CLOCK can be used in Immunohistochemistry (IHC), and anti-BMAL1 and CLOCK can be used for Chromatin Immunoprecipitation (ChIP) assays as well. Please be careful to choose secondary antibodies because some of the products are derived from guinea pig!

Anti-PER2 (Mouse) pAb (Code# PM083) –Rabbit Ig (Aff.)

Anti-PER1(Mouse) pAb (Code# PM091) - Guinea Pig Ig (Aff.)

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Topics: Antibodies

How to detect functional PCSK9 quickly and easily

Posted by Bindi M. Doshi, PhD on Jun 27, 2017 10:00:00 AM

PCSK9 remains an important target in cholesterol research.  One of the hurdles in this research area is determining which PSCK9 form is present and binding with LDLR.  Our new Human PCSK9 Functional Assay Kit is designed to detect active PSCK9 binding with LDLR. 

Read More

Topics: PCSK9, Metabolism, PCSK9 ELISA Kit

Why NCP 3D cell culture method helps your experiments become more real

Posted by M. Mamunur Rahman, PhD on May 18, 2017 10:04:00 AM

3D cell culture innovation ensures that time spent at the bench will correlate to in vivo environments, with possibilities to aid in future discoveries such as drug delivery into tumor cells or understanding tissue microenvironment. Typically, a researcher use a conventional 2D cell culture technique but are limited to what observations they can truly make. NanoCulture Plate 3D platform has been designed to facilitate researchers’ time in the lab.

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Topics: Cell Biology, 3D Cell Culture, NCP

Solving cellular degradation issues with TransFix

Posted by Jon Richards on Apr 25, 2017 9:25:03 AM

Do your samples break down before you can analyze them? TransFix is an easy and effective method to stabilize cellular antigens.

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Topics: TransFix, Cell Stabilization, cell degradation

Why pure exosome isolation matters

Posted by Lise Peeters, PhD on Mar 28, 2017 11:30:00 AM

Exosomes are cell-derived vesicles originating from multi-vesicular bodies and found in biological fluids such as blood, saliva, urine, and breast milk. Sizes of these extracellular vesicles (EVs) range between 30-100 nm. Due to their capacity to transfer proteins, lipids and nucleic acids, exosomes can influence various physiological and pathological functions (Yañez-Mo et al., 2015).

Exosomes play a key role in cell-cell communication and circulate in bloodstream, and therefore, are implicated as a disease biomarker for cancer and immune system disorders. However, there is limited information regarding efficient methods for obtaining pure exosomes. MBL offers a unique exosome purification kit that can help researchers purify exosomes from their sample.

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Topics: Cancer, Exosomes, Liquid Biopsy, Exosome, Biomarker, Purify exosome

Learn about MBL's QC process for providing high quality antibodies!

Posted by Tomohiro Nakajo; Bindi M. Doshi, PhD on Feb 28, 2017 4:40:52 PM

The path that an MBL antibody takes to go from development and manufacturing to the benchtop is intensive and rigorous.  This meticulous attention to detail ensures that every vial a researcher uses maintains high quality and reliability.  Here, we briefly describe the process.

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Topics: Kits and Assays, Quality Control, Antibodies

Quick!  Switch out your peptide!

Posted by Marc Delcommenne, PhD on Jan 20, 2017 11:00:21 AM

The immunotherapy field is making great progress in aiding many disease treatments.  The hope is that one day, personalized immunotherapy can be used so each patient can use their own immune system to overcome their specific disease affliction.  QuickSwitch is a tool for creating custom MHC class I tetramers quickly and easily.

Read More

Topics: Tetramer, QuickSwitch, Peptide, Peptide Exchange

4 Cool Science Discoveries in 2016

Posted by Bindi M. Doshi, PhD on Dec 29, 2016 2:38:31 PM

As 2016 draws to a close, let’s look back on some significant advances made in science.

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Why Autophagy research won a Nobel Prize

Posted by Bindi M. Doshi, PhD on Nov 16, 2016 9:01:39 AM

The process of autophagy was first recognized in the late 1950s and it was thought of as bulk “junk” removal. Then, dedicated scientists did a little more digging and found there is an amazing methodology to the “junk” removal.  It was discovered that there is rhyme and reason for how a cell decides if and when its components should undergo degradation.  Autophagy is rather specific and aids in cell survival by making sure the cell has essential components during times of flux.  Autophagy can be selective (i.e. mitophagy) or non-selective (i.e. starvation-induced).  Using this method, the cell can have non-essential components recycled or send them to onto autophagolysosomes to be degraded.  It is more efficient for a cell to be able to recycle as much as it can, rather than to wait for new proteins to come into the picture.  Autophagy is also crucial for clearing out “junk” such as misfolded or aggregated proteins. Research in autophagy has helped provide a better understanding for how a cell is able to survive even under poor conditions.

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Topics: Autophagy

What does mitochondria have to do with mitophagy?

Posted by Bindi M. Doshi, PhD on Sep 20, 2016 11:42:36 AM

 What is mitophagy? It is when damaged mitochondria are removed from the cell by autophagy.  The damaged mitochondria end up in lysosomes for their final disposal.  This whole process is to maintain and assure proper cellular function.   The importance of this biological process is that it has been implicated in disease states such as cancer and Parkinson’s disease.

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Topics: mitophagy, Autophagy, mitochondria cell death, keima red

Don't be fooled. Not all tetramers are created equal!

Posted by Bindi M. Doshi, PhD; Cheryl A. Guyre, PhD on Aug 24, 2016 11:45:03 AM

Have you seen comparisons of multimer technology claiming to be superior to tetramers? Be sure to ask which tetramers were used in the comparison! MBL tetramers have a clear advantage over academic tetramers and other commercial MHC multimer products, not only due to the reliability and high quality for every lot produced, but also due to the proprietary alpha-3 mutation. This mutation, engineered into the heavy chain of all of our human and macaque class I tetramers, helps decrease non-specific binding, leading to enhanced specificity. Check out the images below to see the details of this important technology!

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Topics: Tetramer

How to choose the right vector for your fluorescent protein needs!

Posted by Tomohiro Nakajo on Aug 2, 2016 10:07:19 AM

MBL’s CoralHue fluorescent product series is composed of many proteins to make your life "brighter"!  We offer expression vectors and cloning vectors. How do you know which vector to use? Learn more about how to choose which vector is right for you.

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Topics: Fluoppi, Fluorescent Proteins, Vectors

How to find and read a publication

Posted by Bindi M. Doshi, PhD on Jun 29, 2016 11:05:05 AM

When you start working in a new lab or working on a new research project, one of the first things to do is look up publications and learn about the field and what has been accomplished. This will help determine the experiments you will run.  It gives you a foundation to build on.  But how do you read a publication?  How do you know it’s worth your while to muster through?  Some publications are miles long with a million figures!  EEKS!  Don’t be frightened.  Keep reading to find out how to tackle a complicated publication and not go crazy.

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Who’s that on my mRNA?

Posted by Bindi M. Doshi, PhD on May 17, 2016 2:44:01 PM

You have an RNA of interest aka your favorite RNA. The question is: which RBPs interact with it? Who are these RBPs and what are their intentions with your precious RNA?

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Topics: RNA, Epigenetics, Gene Regulation, RiboTrap, RBP

Don’t rip your hair out- use our RIP certified antibodies!

Posted by Bindi M. Doshi, PhD on May 2, 2016 7:47:32 AM
What are RBPs (RNA binding proteins)? Very briefly, they are proteins that bind to RNA. (You probably figured that out already.) More importantly, they have a role in regulating RNA as part of the ribonucleoprotein complex (RNP). They are involved in interactions that regulate posttranscriptional  gene regulation1. Not only are RBPs important because of their interactions, but also because it was found that mutations in RBPs can lead to disease formation 2, 3, 4. In order to investigate which RBPs bind with RNAs, a technique called RNP immunoprecipitation (RIP) can be used5.  And in order to have an amazing RIP experiment, one needs an equally amazing antibody.
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Topics: RIP Chip, RNA, Epigenetics, Gene Regulation

Improve your RNA research using our anti-BrdU antibody!

Posted by Miho Shiokawa on Apr 19, 2016 9:13:37 AM

How do you quantify newly synthesized RNA? There are several ways to detect synthesized RNA, but these methods can be inaccurate due to toxicity.

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Topics: BRIC, RNA, Epigenetics, Regulation

Don't FRET- You've got Fluoppi!

Posted by Bindi M. Doshi, PhD on Sep 29, 2015 8:41:14 AM
Visualizing protein-protein interaction (PPI) is pretty neat. You are able to glimpse into a really unique aspect of nature that many people don’t get to see. It’s like watching lions and zebras interact but without the bloody violence.  However, anyone who has tried to visualize two proteins interacting can attest to how difficult it can be. It can involve long hours, uncertainty, and of course, photo bleaching. Blech! MBL’s new technology, Fluoppi, makes visualizing protein-protein interaction a little easier. This technology utilizes fluorescent tags that have a high signal:noise ratio. The only equipment you need is a microscope to observe fluorescence.
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Topics: Fluoppi, Fluorescent Proteins

Colorimetric?  Fluorometric?  How to choose the right platform for your ELISA

Posted by Bindi M. Doshi, PhD on Sep 21, 2015 11:41:52 AM

What happens when you use a black well plate for a fluorometric ELISA assay reading?  What happens when you use a clear well plate for a colorimetric ELISA assay reading?  Well the short answer is that you made the right plate decision!

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Topics: Kits and Assays

Help! My mouse tetramer stained ALL the CD8+ T cells!

Posted by Cheryl A. Guyre, Ph.D. on Aug 26, 2015 3:39:00 PM

You’re sitting at your flow cytometer, staring at your CD8 x tetramer plot in anticipation of a tiny but meaningful group of dots appearing in the upper right quadrant. You hold your breath, click “acquire,” and watch… Wait, what? What’s this ugly diagonal?? How come ALL the CD8 positives are dual positive??! Hey, this is my control mouse! That one should be completely tetramer negative! Yep, I’ve been there too. Classic case of using a CD8 antibody that doesn’t play nice with tetramers.

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Topics: Tetramer

Stop Crying in the Lab: How Cry Antibodies Can Help Your Research

Posted by Deane Buckley on Jul 27, 2015 10:00:00 AM


Figure: Schematic representation of feedback loop involving CLOCK-BMAL1 complex and CRY and PER proteins involved in creating circadian rhythms.

Tiredness and frustration often mount after long nights in the lab. Why can’t our bodies adjust and allow us to maintain our energy through the night? The answer lies in our circadian rhythms. Circadian rhythms are the daily cycle of biological processes such as wakefulness and metabolism1. Many proteins are involved in regulating our circadian rhythms including CRY proteins. This blog post will catch you up on these proteins and their vital role in regulating circadian rhythms.

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Autophagy Watch...What the Flux is that all about?

Posted by Bindi M. Doshi, PhD on Jul 21, 2015 1:49:00 PM

What does Autophagy Flux even mean?  It’s not in the Urban dictionary.  Dear reader, you have come to the right place to learn a little more about autophagy flux and how our Autophagy Watch kit can help you.

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Topics: Autophagy

Give Your Research 100% With a S100 Antibody

Posted by Deane Buckley on Jul 7, 2015 10:00:00 AM


Figure: Schematic representation of S100 proteins in the MAP kinase and NF-kappaB pathways.

S100 proteins are a family of proteins known for their role in a variety of cellular pathways and diseases. This blog post will catch you up on the latest research on these important proteins.

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Topics: Immunology, Apoptosis, Cancer

Elevate Your Research: New Pathways of Study For Your PCSK9 ELISA Kit

Posted by Deane Buckley on Jun 22, 2015 9:00:00 AM

Figure: Schematic representation of PCSK-cIAP1 Binding Assay Kit which can be used to screen inhibitors of PCSK9-cIAP1 interaction during apoptosis.


As discussed in two prior blog posts, PCSK9 has primarily been studied for its role in regulating cholesterol levels and as a target for treatments to lower cholesterol. However, PCSK9 has been found to be involved in many other important pathways.

This blog post will catch you up on the latest research into the diverse functions of PCSK9.

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Topics: Apoptosis

Elevate your Cholesterol Research Part 2: How Our PCSK9 ELISA Kit Can Help You

Posted by Deane Buckley on Jun 8, 2015 11:00:00 AM

Schematic of PCSK9 Binding Kit

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Topics: Metabolism

Elevate Your Cholesterol Research: How a PCSK9 ELISA Kit Can Help You

Posted by Deane Buckley on Jun 2, 2015 10:58:00 AM

Graphic of PCSK9 Pathway. Useful for study of PCSK9 using PCSK9 ELISA Kits and Antibodies 

Ever wonder how cholesterol levels are regulated? One of the major regulators is a molecule called proprotein convertase subtilisin/kexin type 9 or PCSK9 for short! PCSK9 has been implicated in causing hypercholesterolemia (high cholesterol), and diseases such as coronary heart disease1.

This blog post will get you caught up on cholesterol and research on PCSK9's role in cholesterol regulation.

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Topics: Metabolism

Why Smart-IP is the smart way to IP

Posted by Bindi M. Doshi, PhD on May 28, 2015 10:49:05 AM

You have been given the mission to start a new project. A tiny tube is put in your hands and you’re told it contains a potentially interesting protein and your job is to characterize it. After you wipe nervous sweat from your brow, you get down to business. Step one- how to isolate your new buddy? Immunoprecipitation can help with this question! You determine which epitope tag is on your protein and go to to see what you can buy to help this new adventure. You see there are antibodies conjugated to magnetic beads, which help protein pull downs from cell lysates. It's easy, it's fast.  Hmmmm- promising.

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Topics: Epitope Tag

The Fas and the Furious 2: The Importance of Fas in Cancer

Posted by Deane Buckley on May 13, 2015 3:14:46 PM


Given the prominent role of Fas in many important cell functions (7 Facts to Catch You Up to Speed on Fas), Fas has been implicated in a variety of disease states such as cancer. Here are some major findings from recent research about the role of Fas in cancer:

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Topics: Apoptosis, Cancer

The Fas and the Furious: 7 Facts to Catch You Up to Speed on Fas and How a Fas Antibody Can Help Your Research

Posted by Deane Buckley on Apr 30, 2015 11:09:00 AM


Apoptosis induced by Fas antibody

Fas antigen is a receptor protein that has been linked to many diseases such as cancer1 and autoimmune diseases2. Here are seven findings from research on this protein to catch you up to speed on Fas:

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Topics: Apoptosis

Be positive! 5 ways to confirm your MHC tetramer is binding

Posted by Cheryl A. Guyre, Ph.D. on Apr 17, 2015 4:35:17 PM

In the previous Tetramer Tips blog, I suggested ways for you to be a negative Control Freak. Now it’s time to think positive! A positive control for a tetramer is a sample that contains cells expressing the specific T cell receptor of interest, i.e. has the exact specificity of the tetramer. Okay, brace yourselves; I’m going to be frank here.  Having a positive control for tetramer experiments is often a quest for the Holy Grail. In many (most, in fact) cases, you will not have access to a positive control, unless one of your experimental samples happens to show a positive result. In an experiment where no positive events are seen and no positive control was used, you cannot necessarily conclude that the donor/patient/mouse is negative for that T cell specificity, because, heck, maybe you got distracted while pipetting and forgot to add the tetramer to your staining cocktail!  A tetramer experiment with no positive control and no positives in the experimentals is, therefore, uninterpretable. This is the hard truth we must face.

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Topics: Tetramer, Immunology

Attending AACR in Philadelphia?

Posted by Kristin Powers on Apr 16, 2015 10:53:00 AM
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The ABC's of LC3

Posted by Bindi M. Doshi, PhD on Apr 14, 2015 12:22:39 PM

What are LC3 isoforms all about? What do they do?  How are they different?  How are they involved in autophagy?

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Topics: Autophagy

Antinuclear Antibodies and the IFA Test

Posted by Jon Richards on Mar 30, 2015 3:40:59 PM

Antibodies are produced in abundance by the human immune system. The white blood cells are responsible for their manufacture, including lymphocytes (T-cells and B-cells) and antigen presenting cells. Their job is to produce a coordinated response to foreign substances (antigens) as well as to destroy harmful pathogens such as bacteria and viruses. The human body contains vast numbers and varieties of normal and essential human proteins called autoantigens. In some situations the body’s immune system makes an error and recognizes the normally occurring autoantigens as “foreign,” binding to them in order to destroy and eliminate them from the body. A specific subset of antibodies that attack normal proteins found in the nucleus of the cell are called, not surprisingly, antinuclear antibodies, or “ANAs” for short. These misguided antibodies direct their attack against the cell’s nucleic acids and sometimes their associated proteins which are found in or near the nucleus of the cell. Elevated levels of ANAs have been associated with various rheumatic diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis, Sjögren's syndrome, scleroderma, polymyositis, dermatomyositis and various other systemic autoimmune diseases.

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Visiting Experimental Biology 2015 in Boston?

Posted by Kristin Powers on Mar 23, 2015 4:27:48 PM
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Tetramer Tips for Success: How to be a (Negative) Control Freak

Posted by Cheryl A. Guyre, Ph.D. on Mar 20, 2015 10:48:00 AM

While being a Control Freak may not be the best choice for living in spiritual harmony, it is a downright asset in flow cytometry research!  Controls not only help you set up an experiment to get a clear or “true” answer, they can also help you troubleshoot what may have gone wrong when your data just doesn’t look quite right, so that your next attempt will turn out better.  In flow cytometry, controls are critical to help determine “real” events from artifacts.  So, what should you use as controls in tetramer experiments?


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Topics: Tetramer, Immunology

Investigating Parkinson's Disease Part III: The Role of PARK7/DJ-1

Posted by Bindi M. Doshi, PhD on Mar 17, 2015 7:00:00 AM
In the biomedical field, DJ-1 is a target of interest in a variety of disease states.  DJ-1 is considered a contender for a biomarker in the detection of early stage cerebral infraction since it’s concentration increases 3 hours after cerebral injury. When DJ-1 is expressed in excess, it can lead to cancer. For instance, breast cancer patients show increased levels of circulating DJ-1 and anti-DJ-1 antibodies. 3  However, a loss of function can lead to neuodegenerative diseases such autosomal early-onset Parkinson’s disease. 2  
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Topics: Neuroscience

Investigating Parkinson's Disease Part II: The Role of PARK5/UCHL1

Posted by Bindi M. Doshi, PhD on Mar 16, 2015 5:03:04 PM
PARK genes are associated with Parkinson's Disease. The cause of Parkinson's Disease is not currently known and the progression of the disease (on a molecular level) is not well established.  Human UCHL1 ELISA Kit  and Mouse UCHL1 ELISA Kit  has the ability to specifically detect UCHL1.
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Topics: Neuroscience

Investigating Parkinson's Disease Part I: Mitophagy & How to Visualize It

Posted by Glen Molotnikov on Mar 13, 2015 2:47:48 PM

Mitophagy is the selective degradation of old or depolarized mitochondria by autophagy, mitophogy contributes to maintaining a healthy population of mitochondria. Since damaged mitochondria leads to collapsed cell homeostasis, mitophagy is believed to protect against diseases related to mitochondrial dysfunction such as neurodegenerative disorders, most importantly Parkinson's Disease.

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Topics: Fluorescent Proteins, Neuroscience

The Significance of IL-18 in the Inflammatory Response

Posted by Deane Buckley on Mar 9, 2015 10:30:48 AM

Inflammation is regulated by small glycoproteins called cytokines. Cytokines are cell signaling proteins in the immune response pathway1. Il-18 is a cytokine that primarily facilitates Th1-type immunoreactions by acting on T cells.

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Topics: Immunology, IL-18, Immune Response, Allergy

Why bother knowing if you are detecting Pro-IL18 or active IL-18?

Posted by Bindi M. Doshi, PhD on Mar 2, 2015 9:48:00 AM

il-18-01Antibodies are wonderful.  They can act as little detectives to help you determine if the protein you’re interested in is involved in a certain process or help characterize the function.  But what if your favorite protein has two forms?  Is your antibody sophisticated enough to be able to detect one form over the other?  Does this knowledge help you?  How?  IL-18 is one such protein that has two forms.  It is present when it is inactive and present when it is active.  So what is known about IL-18 and its function and the two forms it can exist in?

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Topics: Immunology, IL-18, Immune Response, Allergy

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