title: Prevention of meningo/encephalomyelitis due to Sarcocystis neurona infection in mice is mediated by CD8 cells.
abstract: Immunodeficient CD8 knockout mice were infected with Sarcocystis neurona merozoites, in order to determine the role of CD8 cells in protective immunity. Using a direct agglutination test, all infected mice seroconverted by selected time points. Infected mice developed splenomegaly and bilateral lymphadenopathy. Histological changes included marked follicular development in the spleen, endothelitis and moderate perivascular inflammation in the liver, and meningoencephalitis in the brain. Infected brains were positive for S. neurona by polymerase chain reaction. Corresponding to histopathological changes, there were decreased numbers of B-cells in the spleen. The mice did not have significant memory (CD44hi/CD4) or effector (CD45RBhi/CD4) populations present at the time of euthanasia. Flow cytometry confirmed the lack of CD8 cells. Taken together, these data support previous studies suggesting a critical role for CD8 cells in the prevention of menigoencephalitis in S. neurona-infected mice.
authors.affiliation: Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Phase II, Duck Pond Dr., VMRCVM, Blacksburg, VA 24061-0442, USA. switonsk@vt.edu
authors.forename: Sharon G
authors.initials: SG
authors.lastname: Witonsky
authors.forename: Robert M
authors.initials: RM
authors.lastname: Gogal
authors.forename: Robert B
authors.initials: RB
authors.lastname: Duncan
authors.forename: Heather
authors.initials: H
authors.lastname: Norton
authors.forename: Dan
authors.initials: D
authors.lastname: Ward
authors.forename: David S
authors.initials: DS
authors.lastname: Lindsay
mesh_terms: D000818:Animals; D001835:Body Weight; D001921:Brain / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D020808:Central Nervous System Protozoal Infections / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D007111:Immunity, Cellular; D008099:Liver / Q000473:pathology; D008590:Meningoencephalitis / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D051379:Mice; D018345:Mice, Knockout; D016133:Polymerase Chain Reaction / Q000379:methods; D012522:Sarcocystis / Q000302:isolation & purification; D012523:Sarcocystosis / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D013154:Spleen / Q000473:pathology