title: Role of T cells in granuloma formation induced by Rhodococcus aurantiacus is independent of their interferon-gamma production.
abstract: Intravenous injection of Rhodococcus aurantiacus into mice causes granulomatous inflammation dependent on endogenous interferon-gamma (IFN-gamma). This study investigated the mechanism of granuloma formation with an adoptive transfer system in IFN-gamma knockout (IFN-gamma(-/-)) mice. IFN-gamma(-/-) mice infected with R. aurantiacus did not develop granulomas, and high titres of endogenous interleukin-10 (IL-10) were detected in spleen extracts at 2 weeks after infection. The adoptive transfer of splenocytes from infected wild-type (IFN-gamma(+/+)) mice did not restore granuloma formation, although this treatment diminished IL-10 production in IFN-gamma(-/-) mice. Adoptive transfer of splenocytes from infected IFN-gamma(-/-) mice into infected IFN-gamma(+/+) reduced granuloma formation. These results suggest that splenocytes of IFN-gamma(-/-) mice suppress granuloma formation. On the other hand, although IFN-gamma production induced by R. aurantiacus infection was detected in nude mice, which are deficient in T cells, granuloma formation was not induced in them. However, adoptive transfer of immune splenocytes from either IFN-gamma(+/+) mice or IFN-gamma(-/-) mice could induce granuloma formation. This means that splenocytes of IFN-gamma(-/-) mice have the ability to both induce and suppress granuloma formation. Induction of granuloma is probably dependent on both T cells and IFN-gamma produced by non-T cells. It is suggested that the role of T cells in granuloma formation is not dependent on their IFN-gamma production.
authors.affiliation: Department of Microbiology, School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Japan.
authors.forename: Yimin Masashi
authors.initials: YM
authors.lastname: Kohanawa
authors.affiliation: Department of Microbiology, School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Microbiology, School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Minagawa
mesh_terms: D000193:Actinomycetales Infections / Q000276:immunology*; D000818:Animals; D015169:Colony Count, Microbial; D005260:Female; D006099:Granuloma / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D016219:Immunotherapy, Adoptive; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D012240:Rhodococcus / Q000276:immunology / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D016753:Interleukin-10; D007371:Interferon-gamma