RECOMBINANT CD40 LIGAND EXERTS POTENT BIOLOGIC EFFECTS ON T-CELLS

Murine and human CD40 ligand (CD40L) were recently cloned, expressed, and shown to possess potent activity on human and murine B cells, incl uding stimulation of proliferation and Ig secretion in the presence of cytokines. In addition to its action on B lymphocytes, this report de monstrates that CD40L induced both CD4(+) and CD8(+) T cells isolated from murine lymphoid tissues to proliferate in the presence of submito genic dosages of Con A, PHA, CD3 mAb, and TCR-alpha beta mAb. The pres ence of CD40L during suboptimal TCR stimulation resulted in increased expression of the activation Ags IL-2R alpha and CD69 and increased IL -2 production. Taken together, these results show that CD40L is a pote nt activator of murine T cells and suggest that CD40L is involved in t he regulation of T cell function mediated through T:T cell interaction .