ANTIVIRAL IMMUNE-RESPONSES IN ITK-DEFICIENT MICE

Mice lacking Itk, a T-cell-specific protein tyrosine kinase, have redu ced numbers of T cells and reduced responses to allogeneic major histo compatibility molecules, This study analyzed antiviral immune response s in mice deficient for Itk, Primary cytotoxic T-lymphocyte (CTL) resp onses were analyzed after infection with lymphocytic choriomeningitis virus (LCMV), vaccinia virus (VV), and vesicular stomatitis virus (VSV ), Ex vivo CTL activity was consistently reduced by a factor of two to six for the different viruses, CTL responses after restimulation in v itro were similarly reduced unless exogenous cytokines were added, In the presence of interleukin-2 or concanavalin A supernatant, Itk defic ient and control mice responded similarly, Interestingly, while LCMV w as completely eliminated by day 8 in both Itk-deficient and control mi ce, VV cleared from itk(-/-) mice with delayed kinetics. Antibody resp onses were evaluated after VSV infection, Both the T-cell-independent neutralizing immunoglobulin M (IgM) and the T-cell-dependent IgG respo nses were similar in Itk-deficient and control mice, Taken together, t he results show that CTL responses are reduced in the absence of Itk w hereas antiviral B-cell responses are not affected.