title: Memory T cells protect chicks from acute infectious bronchitis virus infection.
abstract: Infectious bronchitis has remained one of the most difficult to control diseases in poultry since it was first described in 1931. Previous studies demonstrated that primary CD8(+) T lymphocytes collected at 10 days post-infection (p.i.) are important in controlling acute infection. To further investigate the role of memory T cells in protection, T lymphocytes collected from B19/B19 chicken spleens at 2, 3, 4, and 6 weeks p.i. were transferred to six-day-old syngeneic chicks one day prior to challenging with 10(6) EID(50) of the IBV Gray strain. Memory immune T cells collected at 3 to 6 weeks p.i. provided dose responsive protection from clinical illness. The greatest protection was observed after the transfer of 10(7) T cells collected at 6 weeks p.i., whereas T cells collected at 2 weeks p.i. did not protect. Annexin-V staining of the spleen cells demonstrated that the cells collected at 2 weeks p.i. were undergoing significantly more apoptosis than cells collected at 10 days p.i. Specific antibody production in sera collected at 7 days p.i. did not correlate with protection. T cell subtype depletion demonstrated that CD8(+), not CD4(+), T cells were critical. Memory T cells can be detected in peripheral blood mononuclear cells up to at least 10 weeks p.i. These results demonstrated that IBV specific CD8(+) memory T cells generated at 3 to 6 weeks p.i. can protect syngeneic chicks from acute IBV infection.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4467, USA.
authors.forename: Jianwu
authors.initials: J
authors.lastname: Pei
authors.forename: W Elwood
authors.initials: WE
authors.lastname: Briles
authors.forename: Ellen W
authors.initials: EW
authors.lastname: Collisson
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D002645:Chickens; D018352:Coronavirus Infections / Q000276:immunology / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D007156:Immunologic Memory; D066298:In Vitro Techniques; D001351:Infectious bronchitis virus / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D011201:Poultry Diseases / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D007371:Interferon-gamma