Cytochalasin B inhibits lymphotoxin production by antigen-stimulated lymphocytes.

Lymph node cells of rats sensitized with hen ovalbumin produced lymphotoxin after 6 to 12 hours of exposure to specific antigen. Lymphotoxin was assayed by its cytotoxicity for fibroblasts from syngeneic embryos during a 72-hour incubation. Cytochalasin B inhibited lymphotoxin production, as well as later DNA synthesis, at concentrations (0.1 to 5.0 micrograms per milliliter) comparable to those which affect microfilament function and cell motility in other systems, and this inhibition was reversible. Binding of antigen was not affected.