title: Requirement of the initial production of gamma interferon in the generation of protective immunity of mice against Listeria monocytogenes.
abstract: Protective immunity of mice against Listeria monocytogenes, which is mediated mainly by gamma interferon (IFN-gamma)-producing T cells, was induced by immunization with viable bacteria but not with killed bacteria. By comparing mice immunized with either viable or killed L. monocytogenes, it was found that IFN-gamma was produced at the initial stage only after immunization with viable bacteria. This finding prompted us to investigate the effect of neutralizing the IFN-gamma on the final generation of protective T cells against L. monocytogenes. When endogenous IFN-gamma was neutralized by administration of anti-IFN-gamma monoclonal antibody for the initial 2 days in mice immunized with viable bacteria, the generation of protective T cells on day 6 was completely blocked, as revealed by T-cell adoptive transfer. The generation of listeria-specific IFN-gamma-producing T cells was also abolished. These results clearly demonstrated that endogenous IFN-gamma, which is produced at the initial stage of immunization, actually plays a critical role in the generation of protective T cells against L. monocytogenes in vivo. Moreover, this study suggested that the lack of IFN-gamma-inducing ability is responsible for the inability of killed L. monocytogenes to induce protective T cells in mice.
authors.affiliation: Department of Bacteriology, Niigata University School of Medicine, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: I
authors.initials: I
authors.lastname: Kawamura
authors.forename: M
authors.initials: M
authors.lastname: Mitsuyama
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics; D008088:Listeriosis / Q000276:immunology / Q000517:prevention & control*; D051379:Mice; D008809:Mice, Inbred C3H; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors; D014611:Vaccination
chemical_list: D001428:Bacterial Vaccines; D007371:Interferon-gamma