Cloned cytotoxic T cells specific for lymphocytic choriomeningitis virus induce acute disease and primary footpad swelling in infected mice.

Abstract

Lymphocytic choriomeningitis virus (LCMV) infection in mice causes a wide spectrum of diseases with various symptoms, dependent upon virus isolate, virus dose, route of infection, and the immune status of the infected host [4]. When given intravenously (i.v.) or intraperitoneally to immunocompetent mice, it causes acute disease and the virus is usually efficiently eliminated. Major histocompatibility complex (MHC) class I-restricted cytotoxic T cells (CTL) play a key role in this virus elimination [ 10]. This has been shown by adoptive transfer experiments, by evaluating the consequences of anti-Thy 1 treatment, by analysing MHC restriction specificity of effector T ceils, and, more recently, by experiments using cloned LCMV-specific class I-restricted CTL [1]. LCMV injected intracerebrally (i.c.) to immunocompetent C57BL/6J mice causes a severe disease of the central nervous system and death within 6-9 days. This disease has been shown to result from T-cell-dependent [2] damage of infected leptomeningeal cells. The proof for T cell dependence of LCM-disease is, first, T cell-deficient or immunosuppressed mice do not develop LCM-disease [reviewed in 4] and, second, these mice do develop LCM-disease upon adoptive transfer of LCM-immune T lymphocytes [2]. The mechanism by which T cells cause LCM-disease has been under discussion for some time, but the importance of T cell-mediated inflammatory reactions versus direct cytotoxic T cell action is not clearly understood [3, 9]. LCMV-specific CTL clones derived from spleens of C57BL/10J (H-2 b) mice immunized 4-5 weeks earlier with LCMV-Armstrong were prepared by limiting dilution and recloning [7]. The growth of the clones obtained was strictly dependent on the presence of interleukin-2 (IL-2) and required repeated stimulation every 7-10 days with LCMV-infected macrophages. Clone 3.3 (as other clones), when tested in a 51 Cr-release assay, showed high LCMVspecific, H-2Db-restricted lysis of LCMV-infected target cells. When tested by immunofluorescence, these clones were found to be positive for the Thy 1.2 and Lyt 2 but negative for the L3/T4 surface markers. Clone 3.3 was tested for its ability to mediate lethal LCM-disease or to induce a delayed-type hypersensitivity (DTH)-like footpad swelling upon local transfer to appropriate recipients. Groups of 5--10 C57BL/6J mice, immunosuppressed by irradiation (750 r), were infected with 6 x 102 plaque-forming units (PFU) of LCMV-Arm