title: Cytochalasin A inhibits B-lymphocyte capping and activation by antigens.
abstract: Cytochalasin B (CB) has been shown to be a potent depressant of the antigen-induced clone expansion and terminal differentiation of mouse B-lymphocytes to antibody-forming cells. This effect could be the result of the microfilament-disrupting effect of CB with subsequent inhibition of antigen-sIg complex redistribution, a series of events which seems to be necessary for B-lymphocyte activation. CB is not very active in depressing capping and will inhibit glucose transport. To further investigate the mechanism of action of cytochalasins, the effect of cytochalasin A (CA) on cap formation and plaque-forming cell generation was studied, since CA is less inhibitory of glucose transport and more inhibitory of cap formation. The results presented here indicate that complexes of anti-Ig-sIg will be prevented from capping by as little as 1 microgram of CA, a quantity sufficient to depress markedly the generation of plaque-forming cells to SRBC in culture. These results further confirm our conclusion that the depression of B-lymphocyte activation may be related to the depression of cap formation. It also strongly suggested that inhibition of glucose transport can be regraded as a negligible factor in this depression.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D000941:Antigens; D001402:B-Lymphocytes / Q000276:immunology*; D003571:Cytochalasin B / Q000494:pharmacology*; D003572:Cytochalasins / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D007152:Immunologic Capping; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA
chemical_list: D000941:Antigens; D003572:Cytochalasins; D003571:Cytochalasin B; D004121:Dimethyl Sulfoxide