Specificity of the helper T cell for the cytolytic T lymphocyte response to influenza viruses

We have described a model system in which helper T cells are required to mount a primary antiviral cytolytic T lymphocyte response. The radioresistant helper cell can be found in the spleens of mice that have been immunized subcutaneously with influenza viruses 6-8 d previously. These helper cells appear to be type specific but cross-reactive among the subtypes of influenza A viruses. The phenotypes of the interacting cell populations were determined.