Anti-alpha 4 integrin antibody induces apoptosis in murine thymocytes and staphylococcal enterotoxin B-activated lymph node T cells

We have shown that an antibody (9C10) to the alpha 4 integrin induces apoptosis in murine immature CD4(+) CD8(+) thymocytes and in activated (but not resting) mature lymph node T cells. In both cases, apoptosis is blocked by the highly selective protein kinase C (PKC) inhibitor Ro31.8425, suggesting that 9C10 induces signalling through the alpha 4 integrin resulting in PKC activation leading to apoptosis. Overall, our results indicate the potential role of the alpha 4 integrin-mediated interactions in apoptosis induction during T-cell development and following mature T-cell activation.