Peptide or Protein

B7-1 Antigen

A costimulatory ligand membrane glycoprotein that contains a V2 type and C2 IMMUNOGLOBULIN DOMAIN and is expressed by ANTIGEN-PRESENTING CELLS. It binds to CTLA-4 ANTIGEN with high specificity and to CD28 ANTIGEN with low specificity. The interaction of CD80 with CD28 ANTIGEN provides a costimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.