title: CD8+ thymic lymphocytes express reduced levels of CD8beta and increased interferon gamma in cats perinatally infected with the JSY3 molecular clone of feline immunodeficiency virus.
abstract: Biological isolates of feline immunodeficiency virus (FIV) cause a relative expansion of activated single-positive CD8(+) (SP CD8(+)) lymphocytes within the thymus of infected cats. In this study, thymic SP CD8(+) lymphocytes were analyzed from cats inoculated as neonates with a pathogenic molecular clone of FIV, JSY3, which was previously derived from the wild-type biological isolate FIV(NCSU-1) (NCSU-1). Four cats were inoculated intraperitoneally with NCSU-1 and compared with 11 cats inoculated with JSY3. Five control cats matched in litter and age were administered an intraperitoneal sham inoculum. Between 12 and 16 weeks postinoculation, interferon-gamma (IFN-gamma) mRNA was quantified by RT-PCR in freshly isolated thymocytes and peripheral blood mononuclear cells (PBMCs). The quantity of IFN-gamma mRNA was increased more than 10-fold in thymocytes and PBMCs of 13 of 13 FIV-inoculated cats as compared with the sham-inoculated controls. IFN-gamma mRNA coenriched with magnetically sorted CD8(+) PBMCs and single-positive (SP) CD8(+) thymocytes. Cells expressing IFN-gamma mRNA were located within the thymic perivascular zone, along the corticomedullary junction, and adjacent to lymphoid follicles. The expansion of thymic SP CD8(+) cells was associated with an increase in CD8alpha(+)/beta(neg) and CD8alpha(+)/beta(lo) phenotypes, the latter population resembling a previously reported memory/effector peripheral blood cell with FIV suppressor activity. From these data we conclude that JSY3 and NCSU-1 induce similar phenotypic changes in thymic and peripheral blood CD8(+) cells. Thus, JSY3 is pathogenic for the thymus in vivo and will be useful for defining determinants of the CD8(+) cell response in this pediatric AIDS model.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Orandle
authors.forename: P C
authors.initials: PC
authors.lastname: Crawford
authors.forename: J K
authors.initials: JK
authors.lastname: Levy
authors.forename: R
authors.initials: R
authors.lastname: Udoji
authors.forename: G P
authors.initials: GP
authors.lastname: Papadi
authors.forename: T
authors.initials: T
authors.lastname: Ciccarone
authors.forename: A
authors.initials: A
authors.lastname: Mergia
authors.forename: C M
authors.initials: CM
authors.lastname: Johnson
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000096:biosynthesis*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002415:Cats; D016181:Feline Acquired Immunodeficiency Syndrome / Q000097:blood / Q000276:immunology*; D015870:Gene Expression; D016089:Immunodeficiency Virus, Feline / Q000276:immunology* / Q000502:physiology; D007371:Interferon-gamma / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D012333:RNA, Messenger / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D016827:CD8 Antigens; D012333:RNA, Messenger; D007371:Interferon-gamma