| 描述 | The H11-86.1 antibody reacts with CD5 in strains expressing the Ly-1.1 alloantigen (eg, CBA, C3H, DBA/1, DBA/2), but not in Ly-1.2 strains (eg, A, AKR, BALB/c, C57BL, C57BR, C57L, C58, NZB, PL, SJL, SWR, 129). CD5, the major ligand of CD72, is found on thymocytes, T lymphocytes, and a subset of B lymphocytes, but not on NK cells. The level of CD5 antigen detected on T helper cells is somewhat higher than that on T cytotoxic/suppressor and B cells. Few, if any, intestinal intraepithelial lymphocytes bearing the γδ T-cell receptor express CD5. Phenotypic, anatomical, functional, developmental, and pathogenic characteristics of the CD5+ B cells suggest that they may represent a distinct lineage, known as B-1 cells. The frequency of CD5+ B cells shows strain- dependent variation. It has been proposed that CD5 negatively regulates signal transduction mediated by T-cell receptor and B-cell receptor. |
