Novus Biologicals Blog

Posts Tagged ‘Antibody studies’

The CD4 Antibody: More than Just a Cellular Marker

Friday, April 8th, 2011

CD4 is a member of the cluster of differentiation family of proteins, mainly expressed on the surface of thymocytes and a specific subset of mature T-cells. CD4 antibody studies have also shown it expressed on monocytes, cortical cells, microglial cells, dendritic cells and macrophages. The CD4 antibody is widely used in cell marker studies, CD4 being one of the most common CD markers in use. However, the CD4 products in our antibody catalog have also proven useful in cell biology, immunology and cytokine research.

CD4 is a co-receptor for the TCR (T Cell Receptor) heterodimer. It has both intracellular and extracellular domains. The intracellular domain amplifies TCR signalling by activating the tyrosine kinase LCK enzyme, essential to the activated T cell signaling cascade. The four extracellular domains interact directly with MHC class II molecules, which are released by antigen-presenting cells. The main function of CD4 is to increase interaction between the TCR and antigen-class II MHC complex.

Immunocytochemistry/Immunofluorescence: CD4 Antibody

CD4 antibody studies have shown CD4, together with CD3 chains and the CD8 co-receptor, aids signal transduction through the TCR. The CD4 antibody is useful in distinguishing T-helper from T-cytotoxic cells, both of which express the TCR, as CD4 is specific to T-helper cells while CD8 is expressed on T-cytotoxic cells.

The CD4 antibody is central to HIV research, as the viral envelope protein achieves entry into the host cell by CD4 binding, lowering CD4 levels. The CD4 antibody is routinely used in the CD count test, used to monitor CD levels in HIV positive patients.

Novus Biologicals offers many CD4 reagents for your research needs including:

Activation of NF-Kappa B via Coordination of cIAP, TRAF and Kinase NIK

Thursday, March 11th, 2010

Recent antibody studies have suggested that nuclear factor κB-inducing kinase (NIK) is inhibited through proteasome-controlled degradation regulated by TRAF/cIAP proteins. cIAP1 and cIAP2 are fairly recent apoptosis inhibitors and represent some of the newer products in our antibody catalog.

NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) is found in practically all mammalian cells and is a transcriptional factor of DNA. It affects the cellular response to a range of stimuli, including free radicals, UV radiation and stress. It plays an important role in the immune response to pathogens, but disruption of the regulatory pathways can lead to cancer and other diseases.

The TNF receptor-associated factor (TRAF) family are adaptor proteins which link various cell receptors to MAPK signaling cascades, thus activating NF-kB. TRAF proteins are important transducers for the TNF and the IL-1/TLR receptor complexes. They play an important role in the adaptive and innate immune responses.

The C-terminals of TRAF2 and TRAF3 interact with receptor domains following ligand-induced oligomerization. They interact with a number of pro and anti-apoptosis proteins, meaning TRAF signaling can promote either cell death or survival. The cell signaling proteins in our antibody catalog are used for both pro and anti-apoptosis studies in both healthy and cancerous cells.

Recent IHC assays showed that NIK degradation was dependent on a TRAF3/NIK, TRAF2/cIAP1 and TRAF2/cIAP2 regulatory complex. cIAP1 and cIAP2 appeared to play redundant roles in NIK degradation, as deactivation of both proteins was required for non-canonical NF-kB activation and B-lymphocyte survival. The NIK pathway is tightly regulated, meaning a single gene is enough to reverse lethal TRAF deficiency.

Our antibody catalog at Novus Biologicals is constantly being updated to reflect new signaling pathway findings.