CYTO-TOXIC T-MEMORY CELLS IN VIRUS-INFECTION AND THE SPECIFICITY OF HELPER T-CELLS

Abstract

Infective influenza virus primes mice and increases at least 10-fold the level of splenic cytotoxic T-memory and precursor cells in comparison with normal mice. Intranasal virus infection or i.p. injection of infective virus results in frequencies of 1-2 .times. 10-4 cytotoxic T cell precursors in spleen as determined by limiting dilution assays. With both types of immunization, T-helper cells amplifying the generation of T-killer cells are limiting and optimal clone frequencies depend on addition of excess T-helper cells. At least part of the T-helper cells amplifying the generation of cytotoxic T cells are cross-reactive for the type A influenza viruses and therefore have a similar virus specificity to type A influenza-specific cytotoxic T cells (Tc). Help for T-killer cells can be replaced by supernatants derived from concanavalin A-stimulated rat spleen cells, but presence of antigen is still required to stimulate The Tc precursor or memory cells before they respond to antigen non-specific T cell-growth factor(s) present in the stimulated rat spleen cell medium.