title: Essential role of extrathymic T cells in protection against malaria.
abstract: Athymic nude mice carry neither conventional T cells nor NKT cells of thymic origin. However, NK1.1(-)TCR(int) cells are present in the liver and other immune organs of athymic mice, because these lymphocyte subsets are truly of extrathymic origin. In this study, we examined whether extrathymic T cells had the capability to protect mice from malarial infection. Although B6-nu/nu mice were more sensitive to malaria than control B6 mice, these athymic mice were able to survive malaria when a reduced number of parasitized erythrocytes (5 x 10(3) per mouse) were injected. At the fulminant stage, lymphocytosis occurred in the liver and the major expanding lymphocytes were NK1.1(-)TCR(int) cells (IL-2Rbeta(+)TCRalphabeta(+)). Unconventional CD8(+) NKT cells (V(alpha)14(-)) also appeared. Similar to the case of B6 mice, autoantibodies (IgM type) against denatured DNA appeared during malarial infection. Immune lymphocytes isolated from the liver of athymic mice which had recovered from malaria were capable of protecting irradiated euthymic and athymic mice from malaria when cell transfer experiments were conducted. In conjunction with the previous results in euthymic mice, the present results in athymic mice suggest that the major lymphocyte subsets associated with protection against malaria might be extrathymic T cells.
authors.affiliation: Department of Immunology, Niigata University School of Medicine, Niigata, Japan.
authors.forename: M Kaiissar
authors.initials: MK
authors.lastname: Mannoor
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Halder
authors.forename: Sufi Reza M
authors.initials: SR
authors.lastname: Morshed
authors.forename: Anoja
authors.initials: A
authors.lastname: Ariyasinghe
authors.forename: Hanaa Y
authors.initials: HY
authors.lastname: Bakir
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawamura
authors.forename: Hisami
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hiroho
authors.initials: H
authors.lastname: Sekikawa
authors.forename: Toru
authors.initials: T
authors.lastname: Abo
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001323:Autoantibodies / Q000096:biosynthesis; D002449:Cell Aggregation / Q000276:immunology; D002453:Cell Cycle / Q000276:immunology; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology / Q000473:pathology; D008099:Liver / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D016031:Liver Transplantation / Q000276:immunology; D018655:Lymphocyte Count; D008218:Lymphocytosis / Q000276:immunology; D008288:Malaria / Q000276:immunology* / Q000401:mortality / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D010967:Plasmodium yoelii / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D016019:Survival Analysis; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000473:pathology / Q000637:transplantation; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000473:pathology; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D016693:Receptors, Antigen, T-Cell, alpha-beta