[Cytotoxic effect on L-cells of lymphotoxin obtained during hypersensitivity of the delayed type to streptococcal antigens].

A study was made (in vitro) of the cytotoxic action on the mouse L-cells of lymph otoxin obtained in cultivation with a thermostable fraction of streptococcus of the lymph node cells of guinea pigs with hypersensitivity of delayed type to the streptococcus antigens. The cytotoxic action was determined by the calculation of the number of the L-cells preserved in the monolayer after the action on it of a decanted fluid containing lymphotoxin. A marked cytotoxic action on the L-cells was produced only by decanted fluids obtained in cultivation of lymph node cells of guinea pigs sensitized by streptococcus culture with a specific antigen. In cultivation of lymphoid cells of the same animals with a nonspecific antigen (tuberculin) the decanted fluids produced no significant cytotoxic action on mous fibroblasts. The value of the cytotoxic effect depended on the dose of the thermostable fraction, with which the lymph node cells were incubated in the preparation of the decanted fluid, and also on the concentration of the lymph node cells in the initial suspension.