Cytotoxic activity of lymph node cells from mice treated with immunosuppressive antilymphocyte serum.

SummaryA horse antimouse lymphocyte serum was shown to be immunosuppressive in prolonging the survival of C3H skin allografts on Balb/c mice. Despite the immunosuppressive effect of that preparation, however, mixtures of histoincompatible lymph node cells obtained from treated mice showed: (a) an increased local reactivity in the skin of the X-irradiated hamster; (b) a more rapid clearance from those intradermal injection sites; and (c) a significant, in vitro production of nonspecific lymphocytotoxic substance (s). We conclude that the liberation of cytotoxic substance (s) through mouse cell lysis is responsible, in part, for the increased local reactivity of lymph node cells obtained from immunosuppressed mice.