MODULATION BY GAMMA-INTERFERON OF ANTIVIRAL CELL-MEDIATED IMMUNE-RESPONSES IN-VIVO

Mice were infected with lymphocytic choriomeningitis virus and injecte d once 24 h later with a monoclonal antibody directed against gamma in terferon. In comparison with controls, the increase of numbers of CD8( +) T cells and the generation of virus-specific cytotoxic T lymphocyte s in spleens and virus clearance from organs were diminished, as was t he ability of spleen cells to transmit adoptive immunity to infected r ecipients. The same treatment slightly but consistently lessened rathe r than augmented the virus titers early in infection, which was also o bserved in thymusless nu/nu mice. Injection into infected mice of the lymphokine itself in quantities probably higher than are produced endo genously resulted in lower virus titers in spleens but higher titers i n livers, The adoptive immunity in infected mice achieved by infusion of immune spleen cells was not altered by treating the recipients with gamma interferon monoclonal antibody. Such treatment did not measurab ly affect the production of antiviral serum antibodies, We conclude th at in lymphocytic choriomeningitis virus-infected mice, gamma interfer on is needed for the generation of antivirally active CD8(+) T lymphoc ytes, and furthermore that in this experimental model, direct antivira l effects of the lymphokine elude detection.