Cytotoxic T lymphocyte antigen 4 (CTLA-4; CD152) is an immune checkpoint receptor expressed on the surface of activated T cells. During an immune response, T cell activation is initiated when an antigen is presented to the T cell receptor (TCR) by the major histocompatibility complex (MHC) on antigen-presenting cells (APCs). Antigen presentation alone, however, is not sufficient to induce an immune response. Completing the activation process requires a second signal. To maintain activation of an immune response, the primary costimulatory receptor on T cells CD28 binds to the ligands CD80 (B7-1) and CD86 (B7-2) on APCs. When CTLA-4 is upregulated, it competes with CD28 and has a greater affinity for CD80/86. The binding of CTLA-4 to CD80/86 inhibits T cell activation, preserving balance when the immune system is overactive.
CTLA-4 can also be found on regulatory T cells (Tregs), where it is a key driver of their ability to suppress T cell activity. With an almost indefinite lifespan, memory T cells provide long-term immunity. After they have been exposed to tumour antigens, memory T cells immediately mount an immune response against the tumour. The presence of memory T cells is associated with long-term survival and a low risk of tumour recurrence in cancer. Tumour cells utilise the CTLA-4 pathway to suppress the initiation of an immune response, resulting in decreased T cell activation and a reduced ability to proliferate into memory T cells. Targeting CTLA-4 can restore an immune response through the increased accumulation, function and survival of T cells and memory T cells, as well as the depletion of Tregs, and consequently improve the antitumour response.
LIT: CTLA-4 and PD-1 Pathways: Similarities, Differences, and Implications of Their Inhibition: E.I. Buchbinder & A. Desai; Am. J. Clin. Oncol. 39, 98 (2016) • CTLA-4: a moving target in immunotherapy: B. Rowshanravan, et al.; Blood 131, 58 (2018) • Evolving Roles for Targeting CTLA-4 in Cancer Immunotherapy: Y. Zhao, et al.; Cell Physiol. Biochem. 47, 721 (2018)
Biologically Active CTLA-4, CD80, CD86 and CD28 Proteins
See all Biologically Active CTLA-4 proteins here.
See all Biologically Active CD28 proteins by Ancell here.
See all Biologically Active CD80 proteins here.
See all Biologically Active CD86 proteins by Chimerigen here.
See all Biologically Active CD86 proteins by Ancell here.
Biologically Active CD28 Proteins by Chimerigen: CHI-MF-110CD28, CHI-HF-201CD28 & CHI-HF-210CD28
VALIDATED Antibodies for CTLA-4, CD80, CD86 and CD28 Research
See all VALIDATED Antibodies for CTLA-4 Research here.
See all VALIDATED Antibodies for CD80 Research here.
See all VALIDATED Antibodies for CD86 Research here.
See all VALIDATED Antibodies for CD28 Research here.
Originally posted on adipogen.com/ctla-4-cd80-cd86-cd28-network/
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