CD4 Specific Neutra™ Antibody Products

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CD4 (cluster of differentiation 4, aliases Leu-3 or T4), is a glycoprotein of the immunoglobulin superfamily, which contains 4 immunoglobulin domains (D14) exposed on the extracellular cell surface, and serves as a co-receptor molecule for the T-cell receptor (TCR). CD4 is broadly distributed on the surface of immune cells, including monocytes, T helper cells, dendritic cells, and macrophages.

Its Gene ID: 920, UniProtKB ID: P01730, and OMIM ID: 186940.

Functions of CD4

CD4 and Antigen-Presenting

CD4 is a co-receptor of the TCR and aids in the communication between TCR and antigen-presenting cells (APCs). CD4 and the TCR complex bind to the specific regions of the antigen-presenting MHC class II molecule, via the interaction between the D1 domain of CD4 and the β₂-domain of MHC class II molecules. The mechanism makes CD4⁺ T cells specific for antigens presented by MHC II and MHC class II-restricted. CD4 also contains a special amino acid sequence, which enables it to recruit and interact with the tyrosine kinase Lck, to phosphorylate tyrosine residues of ITAMs of CD3, amplifying the signals from the TCR and activating SH2 domain-containing PTK, thus regulating a wide range of downstream signal pathways to trigger T-cell activation.

CD4 CTLs

As the complexity of T helper subset functions is being gradually unveiled, populations of CD4⁺ T cells that possess cytotoxic activity have been described and identified as CD4⁺ cytotoxic T lymphocytes (CD4 CTLs). CD4 CTLs function positively or negatively in a variety of peripheral inflammation sites and affect protective or pathogenic immunity, depending on the specific antigen of the CD4 CTLs. CD4 CTLs are mostly reported to take part in virus infection.

Fig.1 Transcriptional networks and signaling pathways controlling CD4 CTL differentiation.¹

CD4 as a Target for Antibody Development

CD4 plays key roles in antigen presentation and T cell modulation and has attracted much attention as a valuable target in research or treatment of diseases. In the past decades, there have been several CD4-directed antibodies designed and investigated for the treatment of several autoimmune diseases. Recently, an anti-human CD4 antibody has been undergoing clinical trials to evaluate its effect and safety when utilized in the treatment of acute late-onset rejection after transplantation of a renal allograft, and autoimmune diseases like rheumatoid arthritis. Besides, during the past few years, many HIV-1 neutralizing antibodies targeting the CD4-binding site have been designed and investigated and proven to be highly effective, which can provide valuable information for vaccine design and drug development.

Fig.2 Ex vivo treatment of HSC/immune cell grafts by an anti-human CD4 antibody.²

Creative Biolabs offers a variety of anti-CD4 antibody products. These antibodies are recombinantly expressed and could be used for various purposes. Customization of CD4-based monoclonal antibodies or neutralizing antibodies is also available for you here.

REFERENCES

Preglej, Teresa, and Wilfried Ellmeier. "CD4⁺ Cytotoxic T cells–Phenotype, Function and Transcriptional Networks Controlling Their Differentiation Pathways." Immunology Letters 247 (2022): 27-42.
Stahl, Lilly, and Anna Duenkel. "The epitope-specific anti-human CD4 antibody MAX. 16H5 and its role in immune tolerance." Frontiers in Immunology 10 (2019): 440130.

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