title: CD8+ T lymphocytes regulating Th2 pathology escape neonatal tolerization.
abstract: Transplantation tolerance induced by neonatal injection of semiallogeneic spleen cells is associated in several strain combinations with a pathological syndrome caused by Th2 differentiation of donor-specific CD4(+) T lymphocytes. We investigated the role of host CD8(+) T cells in the regulation of this Th2 pathology. IgE serum levels and eosinophilia significantly increased in BALB/c mice neonatally injected with (A/J x BALB/c)F(1) spleen cells when CD8(+) T cells were depleted by administration of anti-CD8 mAb or when beta(2)-microglobulin-deficient mice were used as recipients. In parallel, increased serum levels of IL-5 and IL-13 were measured in blood of tolerant CD8(+) T cell-deficient mice. Whereas neonatally injected mice were unable to generate anti-donor cytotoxic effectors, their CD8(+) T cells were as efficient as control CD8(+) T cells in reducing the severity of Th2 pathology and in restoring donor-specific cytotoxicity in vitro after in vivo transfer in beta(2)-microglobulin-deficient mice. Likewise, CD8(+) T cells from control and tolerant mice equally down-regulated the production of Th2 cytokines by donor-specific CD4(+) T cells in vitro. The regulatory activity of CD8(+) T cells depended on their secretion of IFN-gamma for the control of IL-5 production but not for IL-4 or IL-13. Finally, we found that CD8(+) T cells from 3-day-old mice were already able to down-regulate IL-4, IL-5, and IL-13 production by CD4(+) T cells. We conclude that regulatory CD8(+) T cells controlling Th2 responses are functional in early life and escape neonatal tolerization.
authors: Laboratory of Experimental Immunology, Université Libre de Bruxelles, Brussels, Belgium.
authors: Brigitte
authors: B
authors: Adams
authors: Nathalie
authors: N
authors: Nagy
authors: Frédéric
authors: F
authors: Paulart
authors: Marie-Line
authors: ML
authors: Vanderhaeghen
authors: Michel
authors: M
authors: Goldman
authors: Véronique
authors: V
authors: Flamand
mesh_terms: D000375:Aging / Q000235:genetics / Q000276:immunology; D000818:Animals; D000831:Animals, Newborn / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000637:transplantation*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D007371:Interferon-gamma / Q000502:physiology; D008212:Lymphocyte Depletion; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology / Q000473:pathology; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013154:Spleen / Q000166:cytology / Q000637:transplantation; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D023001:Transplantation Tolerance / Q000235:genetics
chemical_list: D016207:Cytokines; D007371:Interferon-gamma