A role for CD4+ NK1.1+ T lymphocytes as major histocompatibility complex class II independent helper cells in the generation of CD8+ effector function against intracellular infection.

摘要: Major histocompatibility complex (MHC) class II (A beta) knockout mice were vaccinated with ts-4, an attenuated mutant strain of Toxoplasma gondii, which in normal animals induces strong T cell immunity mediated by interferon gamma (IFN-gamma). After challenge the lethal parasite RH, displayed decreased resistance consistent absence CD4+ effectors. Nevertheless, these generated CD8+ lymphocyte effectors capable mediating partial protection through IFN-gamma secretion. Moreover, vivo neutralization experiments indicated that development depends on cells as well interleukin 2 (IL-2). The identity IL-2-producing protective population was further characterized CD4+, NK1.1+ vitro depletion studies and reverse transcriptase-PCR analysis fluorescence-activated sorter (FACS)-purified lymphocytes. These results demonstrate conventional MHC II-restricted lymphocytes, CD8 priming persists mediates to T. gondii. data argue cells, previously implicated initiation helper (Th2) responses their production IL-4, can also play a role alternative IL-2-secreting Th1-mediated host infection.