title: Characterization of extrathymic T cells of chickens.
abstract: The function of CD4+ T cells in antibody production was examined by using T cell subset-depleted chickens. CD4- and CD8-depleted chickens, established by the combination of thymectomy and injection of T cell subset-specific monoclonal antibodies, were immunized with sheep red blood cells (SRBC). Titers of anti-SRBC antibody produced in CD4-depleted chickens were lower than those in control chickens, while no difference in the antibody production was observed between CD8-depleted and control chickens. In chickens depleted of both CD4+ and CD8+ T cells, the recovery of T cells in the periphery was demonstrated starting 3 weeks after T cell depletion. Those T cells recovered in the periphery predominantly expressed CD4 molecules. Although low titers of antibody against SRBC were detected in chickens depleted of both CD4+ and CD8+ T cells, an increase of anti-SRBC antibody production was coincidentally observed with the recovery of CD4+ T cells in the periphery. These results suggest that CD4+ T cells could differentiate in extrathymic environments in chickens, and have a helper function in antibody production similar to that of intrathymic T cells. These extrathymic T cells, however, showed a lower proliferative response to concanavalin A than intrathymic T cells, suggesting that these extrathymic T cells may have some properties distinct from intrathymic T cells.
authors.affiliation: Department of epizootiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Hattori
authors.forename: K
authors.initials: K
authors.lastname: Ohashi
authors.forename: C
authors.initials: C
authors.lastname: Sugimoto
authors.forename: M
authors.initials: M
authors.lastname: Onuma
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D000917:Antibody Formation; D000961:Antilymphocyte Serum / Q000008:administration & dosage; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002645:Chickens / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008212:Lymphocyte Depletion; D012756:Sheep; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000961:Antilymphocyte Serum