Inhibition of macrophage-lymphocyte interaction by cytochalasin B during antigen recognition by T lymphocytes.

The effects of cytochalasin B on functional and physical macrophage-lymphocyte interaction have been examined. Cytochalasin B, an inhibitor of a variety of membrane activities blocks antigen-dependent bindings of immune lymphocytes to macrophages and antigen-triggered lymphocytes proliferation if added at the initiation of culture. Cytochalasin B becomes progressively less inhibitory if addition is delayed by increasing intervals from the onset of culture. Under these conditions neither antigen handling by macrophages nor the proliferative response of lymphocytes to PHA is inhibited by cytochalasin B. These data are interpreted to suggest that cytochalasin B inhibits antigen-specific macrophage-lymphocyte interaction either by inhibition of an initial antigen-independent phase of macrophage-lymphocyte interaction or by interfering with a lymphocyte membrane event necessary for the interaction of the antigen-specific lymphocyte receptor with the macrophage-bound antigenic signal.