Influenza virus-specific T cells lead to early interferon gamma in lungs of infected hosts: development of a sensitive radioimmunoassay.

A sensitive immunoradiometric assay for murine interferon gamma (MuIFN-gamma) has been developed and used reproducibly to measure low levels of MuIFN-gamma in lung lavage samples from influenza-infected mice. In control infected mice, IFN-gamma peaked on day 6, but transfer of virus-specific cytotoxic T cells or T helper cells, which reduced virus replication in vivo in infected hosts, resulted in an earlier peak on day 4.