Cell-Mediated Immunity in Lymphocytic Choriomeningitis I. The Specificity of the Cytotoxic T Lymphocytes

The specificity of cytotoxic T lymphocytes (CTL) generated during murine lymphocytec choriomeningitis (LCM) has been investigated. CTL were obtained from the spleens of mice injected i.p. with LCM virus. The cytotoxic activity of the CTL was tested in an in vitro ⁵¹Cr cytotoxicity assay using infected macrophages or fibroblasts as target cells. At the peak of the cytotoxic T cell response (7–8 days after infection) the cytotoxic action was restricted to syngeneic virusinfected target cells. Using H-2 recombinant mice the target antigen of the CTL generated could be identified as products coded for by either the H-2 K or H-2 D region of the major histocompatibility complex. I region identity between CTL and infected target cells was insufficient for optimal lysis to occur. During the early phase of LCM virus infection there was a transient phase during which noninfected H-2 histocompatible targets were lysed as efficiently as virus-infected target cells. This finding may suggest, that during the early phase of LCM disease self-reactive cytotoxic T lymphocytes are temporarily present in LCM virusinfected mice.