The human CD80 (CTLA-4 Counter-Receptor B7-1) is a recombinant protein consisting of a single glycosylated polypeptide chain with 216 amino acids (35-242aa).

CD80 (B7-1) and CD86 (B7-2) are molecules upregulated on Antigen Presenting Cells (APCs) upon activation of Toll-Like Receptor (TLR) pathways, playing a crucial role in T cell activation by binding to the co-stimulatory molecule CD28. CTLA-4 (CD152) is expressed on activated T cells and binds to CD80 and CD86 with higher affinity than CD28, leading to the suppression of T cell activation. Blocking CTLA-4 signaling prolongs T cell activation and enhances anti-tumor responses. CTLA-4 was the first immune checkpoint targeted for cancer treatment.

Abbreviations: 

B-Lymphocyte Activation Antigen B7, CD80 Antigen (CD28 Antigen Ligand 1, B7-1 Antigen), CTLA-4 Counter-Receptor B7.1, Activation B7-1 Antigen, CD28LG1, CD28LG, CD80 Molecule, T-Lymphocyte Activation Antigen CD80, Costimulatory Factor CD80, CD80 Antigen, B7, Costimulatory Molecule Variant IgV-CD80, LAB7, BB1, B7.1.