CONTROL OF AUTOREACTIVITY .1. LACK OF AUTOREACTIVITY IN MURINE SPLEENS IS DUE TO CONCOMITANT PRESENCE OF SUPPRESSOR AND AUTO-CYTOTOXIC LYMPHOCYTES

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 121  (1) , 179-185
Abstract
To determine if autocytotoxic lymphocytes were naturally occurring in murine spleens, C57BL/6 spleen cells were fractionated on discontinuous BSA [bovine serum albumin] gradients. Autocytotoxicity was assessed in vitro (cytotoxicity of C57BL/6 fibroblasts) and in vivo (splenomegaly and popliteal node enlargement in C57BL/6 mice). A medium density subpopulation of lymphocytes was autocytotoxic and similar to autoreactive lymphocytes produced by the in vitro sensitization of splenic lymphocytes on syngeneic fibroblasts monolayers. The naturally occurring autocytotoxic lymphocytes express no detectable .THETA. antigen, did not adhere to nylon, but did have an Fc receptor. In recombination experiments, BSA-fractionated lymphocytes were incubated with autocytotoxic and sensitized lymphocytes. A light density subpopulation suppressed both autoreactive lymphocyte subpopulations at a 1:50 ratio. The suppressor cells were nylon nonadherent T [thymus derived] lymphocytes. The lack of autoreactivity of unfractionated murine spleen cells is due to the concomitant presence of autocytotoxic and suppressor lymphocytes. If suppressor lymphocytes are selectively removed in vitro, the reactivity of autocytotoxic lymphocytes can be detected.