In this report, we describe a novel activation antigen that appears very early after T cell activation and is absent in resting lymphocytes, through which agonistic proliferative signals can be triggered by mAb binding. It has been designated as activation inducer molecule (AIM) and is a disulphide-linked heterodimeric structure containing two polypeptide chains of Mr 33,000 and 27,000. The expression of AIM can be induced by different activation stimuli such as PMA, PHA, or anti-CD3 mAb, but not by the Ca2+ ionophore A23187, and it precedes the expression of other activation molecules such as 4F2 or the IL-2-R. Once AIM antigens are expressed on lymphocytes after stimulation with submitogenic doses of PMA, the binding of anti-AIM mAbs triggers a strong proliferative response. Furthermore, a comitogenic effect of the anti-AIM mAbs is exerted in the presence of either PHA or anti-CD3 mAb. The activation of lymphocytes through AIM antigens induces both IL-2 and IL-2-R receptor synthesis and is inhibited by anti-IL-2-R mAbs.
Triggering of T cell proliferation through AIM, an activation inducer molecule expressed on activated human lymphocytes.
M Cebrián, E Yagüe, M Rincón, M López-Botet, M O de Landázuri, F Sánchez-Madrid; Triggering of T cell proliferation through AIM, an activation inducer molecule expressed on activated human lymphocytes.. J Exp Med 1 November 1988; 168 (5): 1621–1637. doi: https://doi.org/10.1084/jem.168.5.1621
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