LYT-2 negative and T cell growth factor independent cytotoxic T lymphocyte hybridomas

Role of LFA-1 integrin in the control of a lymphocytic choriomeningitis virus (LCMV) infection

Leukocyte function-associated antigen 1 (LFA-1) is the most widely expressed member of the β2 integrin family of cell-cell adhesion molecules. Although LFA-1 is thought to regulate multiple aspects of T cell immunity, its role in the response of CD8⁺ T cells to viral infections remains unclear. Indeed, compelling clinical evidence shows that loss of LFA-1 function predisposes to infection in humans but animal models show limited to no susceptibility to infection. Here, we addressed this conundrum in a mouse model of infection with lymphocytic choriomeningitis virus (LCMV), where CD8⁺ T cells are necessary and sufficient to confer protection. To this end, we followed the fate and function of wild-type and LFA-1 deficient virus-specific CD8⁺ T cells and assessed the effect of blocking anti-LFA-1 monoclonal antibody in the outcome of infection. Our analysis of viral clearance and T cell responses using transcriptome profiling reveals a role for LFA-1 as a gatekeeper of effector T cell survival and dysfunction that when defective can predispose to LCMV infection.

Lymphoid cell surface interaction structures detected using cytolysis-inhibiting monoclonal antibodies

We screened monoclonal antibodies obtained by xenogeneic immunization for their capacity to inhibit T cell-mediated cytolysis. These antibodies fell into two classes according to the cell structures they recognized, of 30-35 K and 94-180 K apparent molecular weight, respectively. The main features of these structures and of their interaction with the corresponding antibodies were reviewed. The inhibition of cytolysis by these antibodies was shown to occur mainly at the effector cell level, at the recognition stage of cytolysis, and to depend on the nature of target cells, effector cells, and link between these cells. T cell functions other than cytolysis were also inhibited by some of these antibodies. We considered various possible mechanisms to account for the inhibition of cytolysis by these mAb. We favor an hypothesis based on inhibition by these mAb of lymphoid cell surface interaction structures. This hypothesis was discussed within the general framework of cell interaction structures in immunological and non-immunological experimental systems.