Temporal dependence of the inhibition by cytochalasin B of antigen-initiated migration inhibition factor production.

The effects of cytochalasin B on the antigen recognition process have been examined using an in vitro assay of macrophage-inhibition factor (MIF) production by activated guinea pig T lymphocyte-enriched populations. The data indicate that cytochalasin B inhibits MIF production if added at the initiation of culture but not if added 2 hr after antigen. These data are interpreted as consistent with either an inhibition by cytochalasin B of the physical assoication of antigen-bearing marcrophage and lymphocytes or with an inhibition of the access of antigen to the T lymphocyte receptor.