cAMP accumulation in T-cells inhibits anti-CD3 monoclonal antibody-induced actin polymerization

The results presented in this report offer a novel explanation for how stimulation of the beta-adrenergic receptor (beta AR) inhibits the ability of T cells to proliferate after interaction with immobilized anti-CD3 monoclonal antibody (mAb). Accordingly, T cells binding to immobilized anti-CD3 mAb but not anti-CD4 mAb undergo time-dependent F-actin assembly with concomitant formation of pseudopodia. This process is completely inhibited in the presence of isoproterenol (ISO) indicating that stimulation of the beta AR on T cells interferes with the biochemical processes responsible for the assembly of actin. To confirm these observations, we quantitated the formation of F-actin in T cells stimulated with immobilized anti-CD3 mAb in the presence of cAMP elevating agents. The results show that stimulation of the beta AR on T-cells, as well as the addition of forskolin or dibutyryl cAMP, abrogates the formation of F-actin.