title: Characterization of T cells that confer a high degree of protective immunity against tuberculosis in mice after vaccination with tumor cells expressing mycobacterial hsp65.
abstract: Mice vaccinated by injection with tumor cells expressing the Mycobacterium leprae gene for hsp65 acquire a remarkably high degree of protection against challenge with Mycobacterium tuberculosis. We used limiting-dilution analysis to assess the frequency of CD4+ CD8- and CD4- CD8+ splenocytes responding to mycobacterial hsp65 in such vaccinated mice. Cells of both phenotypes were present at very high and equal frequencies (approximately 1:100). Vaccination with live Mycobacterium bovis BCG also increased the frequencies of both phenotypes of hsp65-reactive cells equally (to approximately 1:2,500), whereas vaccination procedures that were not protective, with either dead BCG, hsp65 protein in incomplete Freund's adjuvant, or hsp65 mixed with tumor cells, resulted in preferential increase in CD4+ CD8- cells. Twelve CD4+ CD8- and twelve CD4- CD8+ hsp65-responsive T-cell clones were obtained and characterized. All showed conventional antigen recognition via major histocompatibility complex class II and class I pathways but differed in secretion of gamma interferon and interleukin 4 and cytotoxicity. In tests of antimycobacterial activity against M. tuberculosis, both in infected macrophages in vitro and by adoptive transfer of protection with T-cell clones injected into irradiated mice, the most effective clones were the most cytotoxic and secretion of gamma interferon made only a secondary contribution.
authors.affiliation: Department of Parasitology, Microbiology and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
authors.forename: C L
authors.initials: CL
authors.lastname: Silva
authors.forename: M F
authors.initials: MF
authors.lastname: Silva
authors.forename: R C
authors.initials: RC
authors.lastname: Pietro
authors.forename: D B
authors.initials: DB
authors.lastname: Lowrie
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D001500:BCG Vaccine / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018834:Chaperonin 60; D018833:Chaperonins / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D016219:Immunotherapy, Adoptive; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009166:Mycobacterium leprae / Q000276:immunology*; D009374:Neoplasms, Experimental / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014376:Tuberculosis / Q000276:immunology* / Q000517:prevention & control*; D014611:Vaccination
chemical_list: D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; D018834:Chaperonin 60; D016207:Cytokines; C074119:heat-shock protein 65, Mycobacterium; D018833:Chaperonins