Antibody News

CD80: A co-stimulator of T cell activation

Friday, December 19, 2014 - 12:55

CD80 is a 60kD single chain type I transmembrane glycoprotein that is a member of the immunoglobulin family. CD80 is expressed on activated B- and T-lymphocytes, as well as a subpopulation of previously activated B-cells, but not on the majority of resting B-cells in peripheral blood. It is also found constitutively expressed on dendritic cells and macrophages.  CD80 and CD86 are both ligands for two structurally similar molecules expressed on T-lymphocytes - CD28 and CTLA4/CD152. Binding to these molecules is a potent co-stimulatory CD3 complex-dependent signal for T-lymphocyte activation, cytokinse production, and T-cell tolerance establishment. The roles of co-stimulatory (CD28) and co-inhibitory (CTLA4) molecules in T-cell receptor (TCR) signaling are nicely published by Chen in a Nature Reviews in Immunology1....

Collagen I: Tissue origin detection has begun

Thursday, December 18, 2014 - 14:47

The extracellular matrix (ECM) is the external framework found between individual cells that comprise higher order structures like tissues and organs. The ECM composition of vertebrates is dominated by a class of molecules known as collagens - each with unique features suited for a particular function and location. Collagen proteins are made up of three subunit polypeptides that vary in length. Through a unique repeated (Gly-X-Y) sequence, these components associate to form a structurally regular triple helix. Collagen type I is one of the most common collagen forms and is found in a wide variety of areas including skin, tendon, vascular ligature, organs, and bone. Because of collagen I’s basic and fundamental role in guiding ECM architecture, its identification and detection is useful in the classification and verification of tissue-specific origins, and sample tissue typing.

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B-cell activating factor (B7H4, B7S1, immune co-stimulatory protein B7-H4)

Wednesday, December 17, 2014 - 14:30

B7H4 is a co-stimulatory protein though to function as a negative regulator of T-cell mediated immunity by blocking proliferation, cell cycle progression and interleukin-2 (IL-2) production. Because B7H4-deficient mice are only minimally affected, it appears that B7H4 is involved in fine tuning of the T-cell mediated immune response. B7H4 is expressed on activated T-cells, B-cells, monocytes, and dendritic cells and exists in three different isoforms. Its aberrant expression has been associated with a variety of cancers such as lung, breast, and ovary, and it may hold promise as a prognostic marker for renal cell carcinoma (RCC). Sarafian et al examine the expression profile of human blood group antigenic determinants such as B7H4 in normal human tissues1.

More immunology profiling studies from another...

CD68 (Cluster of differentiation 68, GP110, LAMP4, SCARD1)

Monday, December 15, 2014 - 14:29

CD68 belongs to a growing family of hematopoietic mucin-like molecules known as lysosomal/endosomal-associated membrane glycoproteins (LAMPs). Other LAMP family members included leukosialin, stem cell antigen CD34, and GlyCAM-1. CD68 encodes a 110-kD transmembrane glycoprotein with high levels of expression in human monocytes and tissue macrophages. CD68 binds lectins through a heavily glycosylated extracellular domain. It has also been found to be a member of the scavenger receptor family, whose main purpose is to clear cell debris, regulate phagocytosis, and recruit macrophages. CD68 transcripts are absent or present at very low levels in many hematopoietic lines, but can be induced by exposure to phorbol myristic acid (PMA/TPA).

Horny et al employed the CD68 antibody to distinguish between normal and neoplastic human monocytes, mast cells, and macrophages1. Their findings provide valuable diagnostic...

PCNA (Proliferating cell nuclear antigen, polymerase delta auxiliary protein)

Friday, December 12, 2014 - 14:19

PCNA is a nuclear protein essential for DNA replication as well as DNA excision and mismatch repair pathways. It coordinates the recruitment and association of needed components during both of these processes, both of which are essential for cell cycle regulation and cell response to stress.  Through the symmetric association of three identical monomers, PCNA forms a toroidal, ring-shaped structure that encircles DNA. This serves as the scaffold upon which polymerases and other proteins dock and associate.  It has been demonstrated that PCNA binds directly to downstream signaling molecules such as CDK inhibitor p21, endonucleases Fen1 and XPG, and DNA cytosine 5-methyltransferase (MCMT).

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FMS-like tyrosine kinase 3 (FLT3/FLK2)

Thursday, December 11, 2014 - 14:31

FLT3 is a Type III tyrosine kinase cell surface receptor found on primitive bone marrow stem cells. The FLT3 ligand is a hematopoietic growth factor that stimulates cells via a set of structurally related tyrosine kinase receptors.  This FLT3 Ligand promotes the differentiation of multiple hematopoietic cell lineages and is expressed as a non-covalently-linked dimer by T-cells, bone marrow, and thymic fibroblasts. Downstream events in the FLT3 pathway include the expansion of monocytes and immature dendritic cells, B-cell differentiation, natural killer (NK) cell development, and myeloid differentiation of hematopoietic stem cells.

Because FLT3 overexpression and mutations are highly associated with...

L-selectin (CD62L antigen, Leukocyte surface antigen Leu-8)

Wednesday, December 10, 2014 - 14:33

L-selectin is a member of the selectin family of glycoprotein adhesion and homing receptors that recognize sialyated carbohydrate groups and regulate lymphocyte-endothelial cell interactions. It is a type I transmembrane cell adhesion molecule (CAM) and is constitutively expressed on all classes of circulating leukocytes including lymphocytes (excluding memory T-cells), monocytes, and polymorphonuclear (PMN) cells. L-selectin is also expressed on bone marrow myeloid progenitor cells, erythroid precursor cells, and some thymocytes. Knockout mice studies implicate L-selectin in health and disease conditions – leukocyte recruitment to lymph nodes, acute and chronic inflammation, etc.  

A detailed overview of the L-selectin signaling cascade (including currently...

Growth hormone (GH, somatotropin, hGH, pituitary growth hormone)

Tuesday, December 9, 2014 - 14:53

GH is a member of the large family of growth factors that includes prolactin, placental lactogens, proliferins, and somatolactin. Additionally, GH is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. Release of GH into the circulation is mediated by the concerted actions of the hypothalamic hormones-GH-releasing hormone (GHRH) and somatostatin (SST), as well as through signals from the periphery-ghrelin and leptin. At least four alternatively spliced isoforms of GH are known. It is a multipotent and fundamental peptide hormone that stimulates growth, cell reproduction, and regeneration (see Matsuzaki et al for review) 1. Body growth stimulation occurs through the primary pathway of stimulating the liver (and other tissues) to secrete IGF-1.

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GAPDH: More than a housekeeping gene

Monday, December 8, 2014 - 14:41

GAPDH is a 146kD tetramer glycolytic pathway metabolic enzyme composed of four 30-40 kDa subunits. It is responsible for reversibly phosphorylating its substrate glyceraldehyde 3-phosphate within the glycolytic pathway.  Apart from its role in glycolysis, GAPDH may have other roles such as transcriptional activation. Due to its housekeeping role, GAPDH is highly expressed in almost all tissues, allowing its use as an internal loading control (traditionally for mRNA expression comparisons, but also in protein studies. The GAPDH antibody is an established standard as evidenced by its usage in a wide range of scientific research and published literature.  GAPDH is reported to bind to a variety of other proteins, including the amyloid precursor protein. Associations with actin and tubulin have also been reported. The protein may also have a role in the regulation of apoptosis. Shin et al employed the...

MMP24 (Matrix metalloproteinase-24, matrix metalloproteinase-25, MT5-MMP)

Thursday, December 4, 2014 - 14:37

MMP24 is an extracellular matrix (ECM) degradative peptidase enzyme that is a member of the large family of matrix metalloproteinases (MMP). Each MMP has a different substrate specificity, and the aberrant or derailed expression of these is strongly correlated with unregulated events such as tumor invasion, metastasis, angiogenesis, and arthritis. This is in contrast to the tightly controlled normal physiological processes such as tissue remodeling, reproduction, rebuilding, and embryonic development. Deregulation often occurs through the loss of negative checks. Most MMP's are secreted as inactive proteins which are activated upon cleavage by extracellular proteinases. However, this protein is unusual is that it belongs to the membrane-type MMP (MT-MMP) subfamily – it contains a potential transmembrane domain suggesting that proteins of this subfamily are expressed at the cell surface rather than secreted. MMP24 activates MMP2 by cleavage. MMP24 is...

B-cell activating factor (BAFF) - keep the level steady!

Wednesday, December 3, 2014 - 15:22

BAFF belongs to the tumor necrosis factor (TNF) family, and its downstream signaling plays a critical role in B-cell survival and maturation. BAFF overproduction is associated with a variety of autoimmune diseases. BAFF is the functional ligand for three receptors:
BAFF-R, transmembrane activator and calcium modulator (TACI), and B-cell maturation Ag (BCMA). Varzaneh et al extensively review the contributions of a huge array of interleukins (ILs), interferons, tumor necrosis factor alpha (TNFa), APRIL, and BAFF in common variable immunodeficiency (CVID) disease1. Their study maps in detail the profiles of various cytokines as well as outlines their therapeutic potential. Another recent autoimmune review from Lanteri‘s group examined the role of serum free light chains of immunoglobulins (sFLC) in systemic sclerosis (SSc)2.  Using a...

GPNMB (glycoprotein non-metastatic melanoma protein B, osteoactivin)

Tuesday, December 2, 2014 - 15:19

GPNMB is a type I transmembrane glycoprotein with homology to the PMEL17 precursor, a melanocyte-specific protein. Two transcript variants encoding different isoforms exist.GPNMB is expressed in minimally (but not highly) metastatic human melanoma cell lines and xenografts and may be involved in the delay and reduction of metastatic potential and growth. GPNMB appears to promote migration, invasion, and metastasis of a wide array of tumor cells and is therefore a promising and emerging target for drug development. Fiorentini’s group in the University of Brescia recently published that GPNMB acts on several prostate cancer cell lines by upregulating the metalloproteinases MMP2 and MMP91.  It was originally discovered in bone cells and also appears to be linked to eye syndromes such as iris...

VEGF: Vascular endothelial growth factor

Monday, November 24, 2014 - 09:36

VEGF is homodimeric, disulfide-linked glycoprotein cytokine that serves as the ligand for FLT1 (VEGFR-1 receptor) and FLK1 (VEGFR-2 receptor) tyrosine kinases. It is a key modulator of physiological angiogenesis, vasculogenesis, and endothelial cell growth during basic developmental processes such as embryogenesis, skeletal growth, and reproductive functions. The VEGF ligand/receptor signaling system stimulates endothelial cell proliferation, blood vessel permeabilization, cell migration, and inhibition of apoptosis. There exist several widely expressed isoforms (VEGF189, VEGF165 and VEGF121) as well as some that are not as commonly found (VEGF206 and VEGF145). The basic VEGF189 isoform is cell-associated after secretion and is bound avidly by heparin and the extracellular matrix (ECM).

TLR4 - A Guardian of Innate Immunity

Friday, November 21, 2014 - 09:16

Toll-like receptor 4 (TLR4) belongs to the family of Toll-like receptors (TLR), and plays a main role in pathogen recognition and innate immunity system activation. The TLR family members are highly conserved proteins that all contain a high degree of structural and functional homology in organisms from Drosophila all the way up to humans. TLRs regulate the cellular cytokine production required for efficient innate immunity development through their recognition of pathogen-associated molecular patterns (PAMPs) expressed across a wide range of ligands, including infectious agents. TLR4 recognizes the Gram-negative bacterial membrane component lipopolysaccharide (LPS).

Immunohistochemistry-Paraffin: TLR4 Antibody Immunohistochemistry-...

Ly6G - a marker for monocytes, granulocytes and neutrophils

Thursday, November 20, 2014 - 09:22

Ly6G (Lymphocyte antigen 6 complex locus G6D) is a 21-25kD glycosylphosphatidylinositol (GPI)-linked differentiation antigen that is expressed by myeloid-derived cells in a tightly developmentally-regulated manner in the bone marrow. Monocytes express Ly6G transiently during bone marrow development, while Ly6G expression in granulocytes and peripheral neutrophils directly correlates with the cell’s level of differentiation and maturation. This hallmark makes Ly6G a good marker for these particular cell populations. Ly6G has also been implicated in the development of antitumor responses.

Flow Cytometry: Ly-6G Antibody Flow Cytometry: Ly-6G Antibody

 

Researchers from the Genetics Institute at Andover used the...

TLR2 - I can recognize many foreign pathogens!

Tuesday, November 18, 2014 - 09:06

TLR2 is a member of the broad family of Toll-like receptors (TLR) that play an important role in pathogen recognition and innate immunity. TLRs, like other pattern recognition receptors (PRRs), recognize endogenous ligands released during cell or tissue damage (DAMPs) as well as exogenous, pathogen associated ligands from bacteria or viruses (PAMPs).  Upon recognition of a specific ligand, PRRs activate host defense processes including cytokine and inflammatory mediator secretion, and innate immune cell activation and proliferation.  TLR2 recognizes the bacterial cell wall component, peptidoglycan. Recent Studies

  • A TLR2 antibody expression profiling study published by Palladino et al uncovered detailed profiles for over a dozen TLR family members in rat male reproductive tract organs and tissues1.
  • A Dutch research group used a TLR2 antibody to create similar expression...

Beta-catenin - I am versatile!

Monday, November 17, 2014 - 09:01

Beta-catenin is a cytosolic, 88 kDa intracellular protein associated with cell surface cadherin glycoproteins. It is a member of the larger calcium-dependent catenin family that includes alpha-catenin, beta-catenin, and gamma-catenin (also known as plakoglobin). Beta-catenin enters the nucleus to interact with TCF/LEF (Lymphoid enhancer factor-1) transcription factor family. It is normally inhibited by the GSK (glycogen synthase kinase) or CK1 (casein kinase 1) as phosphorylation of beta-catenin targets it for ubiquitin-mediated degradation.  The beta-catenin/TCF pathway is involved in T-cell development and differentiation and may be a target for immune and autoimmune disorders.

BAG3 - Hsp70 is my friend!

Friday, November 14, 2014 - 08:50

The BAG proteins are a large family of chaperone regulators governing a wide range of cell processes such as proliferation, survival, stress response, tumorigenesis, neuronal differentiation, growth arrest and apoptosis as reviewed in Takayama et al1. BAG proteins are co-chaperones that interact with several forms of the chaperone heat shock protein 70 (Hsp70) – the association allows them to both positively and negatively regulate Hsp70. Family members include BAG-1 and its various isoforms, BAG-1L, BAG2, BAG3, BAG4 (SODD), BAG5, and BAG6 (Scythe, BAT3). BAG3 is involved in chaperone-mediated selective autophagy. BAG3 antibody was used by Liao et al in their expression studies in human pancreatic cancer tissues and cell lines2. With the...

Factor VII - A Major Protein in Blood Coagulation

Friday, October 31, 2014 - 13:14

Factor VII (coagulation factor VII) is a 50 kD multidomain single chain plasma glycoprotein synthesized in the liver. It is a vitamin K-dependent serine protease essential for the extrinsic pathway of hemostasis, or blood coagulation. Factor VII circulates in the blood in a zymogen form that is converted to an active form (via factor IXa, factor Xa, factor XIIa, or thrombin). Rare bleeding disorders (RBDs) are rare within the general community, but present both a diagnostic and effective treatment challenge due to the highly variable range in clinical presentation and cause. Defects in Factor VII cause coagulopathy and hemorrhagic disease, which range in severity from mild tolerable events to acutely severe and repeated hemarthroses and life-threatening intracerebral hemorrhages.

There is nothing beta than PKC Alpha

Friday, October 31, 2014 - 12:38

cAMP-dependent protein kinase (PKA) is a Ser/Thr protein kinase that is highly conserved between species. Three distinct catalytic (C) subunits have been identified, designated C-alpha, C-beta and C-gamma, where C-alpha and C-beta are most closely related. PKA mediates a variety of diverse cellular responses (cell growth and proliferation, ion transport, triglyceride storage and metabolism regulation, embryonic development, and gene transcription) in virtually all eukaryotic systems via phosphorylation of a wide range of downstream target proteins in both they cytoplasm and nucleus. Elevation of cAMP triggers the following cascade of events: PKA translocation from the cytoplasm to the nucleus, transcription factor cAMP response element binding protein (CREB) phosphorylation, TFIIB binding to the TATA-box-binding protein TBP1, and lastly, phosphorylated CREB binding to the pol II transcription initiation complex.

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CRISPR-associated system 9 (CAS9)

Thursday, October 30, 2014 - 14:31

CAS9 is a novel DNA-cutting enzyme that is the main component of an intrinsic DNA editing system used by bacteria to kill attacking viruses. Clustered regularly interspaced short palindromic repeats (CRISPR) are distinct features of most bacterial genomes, and thought to be involved in resistance to bacteriophages. CRISPR is a primitive immune system of sorts that determines resistance specificity, as published by the Danisco Corporation in Science1. Because of CAS9’s ability to allow for parallel targeted DNA edits has huge implications in a wide range of applications, including gene therapy, agricultural advancements, and energy-producing microbes for biofuels. Deltcheva et al investigated mechanisms of CRISPR RNA maturation and identified a small trans-encoded RNA that appears to direct RNA-mediated immunity2.

Scary Protein Names: Halloween Infographic Edition

Wednesday, October 29, 2014 - 11:41

Check out some of the spooky protein names as we approach Halloween in our Scary Protein Name Infographic. Learn about their function, gene name, molecular weight and subcellular location. Featured proteins in this infographic include: SCARE1, DEAD Box Protein 60, Spo Spook, BAT3, BOO and GST. Happy Halloween!

Scary Protein Names

Novus Biologicals offers research reagents mentioned in this post including:

Ready, set, activate: (IL2RA/CD25)

Monday, October 27, 2014 - 15:02

The Interleukin 2 Receptor alpha and beta chains, along with the common gamma chain, comprise the high affinity IL2 receptor(IL2R) that is present on both mature activated T- and B-cells, as well as early progenitors of T- and B-cells (thymocytes, pre B-cells, and T-regulatory cells). Formation of homodimeric alpha chains (IL2RA) results in a low affinity receptor, while homodimeric beta chains (IL2RB) produce a medium affinity receptor. IL2RA is normally an integral membrane protein, but a soluble IL2 Receptor alpha has been isolated and appears as the result of extracellular proteolysis. IL2RA plays a key role in lymphocyte differentiation, activation, and proliferation.

Immunohistochemistry-Paraffin: IL2RA/CD25 Antibody ...

CD8 alpha - Marker for cytotoxic T lymphocytes

Friday, October 24, 2014 - 15:01

The T-cell co-receptor CD8 is a cell-surface glycoprotein that bridges the lipid bilayer by interacting externally with ligands, such as major histocompatibility complex (MHC) class I, as well as internally with signaling molecules such as tyrosine kinase p56 lck. CD8 associates with lck through a zinc clasp structure and down regulates major Th2-type cytokine production. It is expressed on thymocyte subsets and cytotoxic T-cells and exists as either as a disulfide-linked homodimer or as a heterodimer of CD8 alpha and CD8 beta.  CD8 plays an important role in T-cell development in the thymus and T-cell activation in the periphery.

Immunohistochemistry: CD8 alpha Antibody Immunohistochemistry: CD8 alpha Antibody

Early studies...

Lymphocyte activation gene 3 (LAG3): No lag time in immune response

Thursday, October 23, 2014 - 14:44

The LAG3 protein belongs to the Ig superfamily and contains 4 extracellular Ig-like domains (D1-D4). This molecule plays an key role in the immune response through negative regulation of T-cell proliferation, function, and homeostasis. It is required for maximum natural and induced regulatory T-cell function. LAG3 is closely related to the T-cell co-receptor CD4, and like CD4, binds to MHC class II molecules - but with a significantly higher affinity. It is expressed exclusively in activated T- and natural killer (NK) lymphocytes.

Western Blot: Lymphocyte Activation Gene 3 Antibody Western Blot: Lymphocyte Activation Gene 3 Antibody

 

Studies with the...

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