Bone marrow macrophages process exogenous Toxoplasma gondii polypeptides for recognition by parasite-specific cytolytic T lymphocytes.

摘要: CD8+ T cells from mice vaccinated with an attenuated strain of Toxoplasma gondii have previously been shown to cytolytic activity against bone marrow macrophages (BMM phi) preincubated a soluble tachyzoite extract. In the present study, we show that class I-transfected L differ BMM phi in although both cell types are recognized CTL after infection, only killed sensitization Gel filtration studies indicated T. Ag responsible for macromolecules M(r) > or = 12,000. contrast, peptides derived by tryptic digestion this material were found sensitize transfected and phi. Although exogenous beta 2-microglobulin markedly enhanced peptide phi, no such effect was observed using macromolecular preparation. This result suggests requirement cellular internalization processing I-restricted recognition. related experiments, infected Ag-sensitized express cross-reactive epitopes, as determined cold target inhibition studies. Supernatant 100,000 x g centrifugation extract had potent sensitizing activity, anion exchange chromatography most associated single fraction. The p30 not detected immunoblot analysis biologically active supernatant chromatographic fractions. These findings establish feasibility identifying parasite effectors direct fractionation proteins coupled targets.