title: Kinetics of early T-cell repopulation in fully xenogeneic chimeras (F344 rat----B10 mouse): evidence for rat T-cell maturation in a xenogeneic mouse thymus.
abstract: We recently reported the model of fully xenogeneic chimerism achieved by transplantation of rat bone marrow into mouse recipients (F344 rat----B10 mouse), resulting in stable long-term rat lymphoid chimerism. We have now extended this model to examine whether developing precursor rat T cells from rat bone marrow stem cells can undergo normal differentiation in mature lymphocytes under the influence of a xenogeneic mouse thymus. We examined thymic and splenic lymphoid cells from fully xenogeneic chimeras starting 1 week after bone marrow transplantation to characterize early T-cell repopulation and phenotype. Our data suggest that developing rat precursor T cells are able to undergo normal differentiation in the mouse thymus. The first precursor T cells appeared 2 weeks after reconstitution and by week 10 accounted for more than 90% of thymocytes present in the chimeras. In chimeras, developing rat T lymphocytes in the mouse thymus exhibited an immature pattern (Thy 1.1+, alpha beta-TCRdull, CD4+ plus CD8+) when analyzed by flow cytometry. This pattern was similar to a normal rat. In contrast, splenic T-lymphoid cells showed a mature rat phenotype (Thy 1.1-, alpha beta-TCRhi, CD4+ or CD8+), again similar to a normal rat. This development began 2 weeks after bone marrow transplantation, and both thymus and spleen from chimeras exhibited "normal" rat T-cell staining profiles by 10 weeks after reconstitution. Overall, these data indicate that developing rat T cells are capable of undergoing normal maturation in a xenogeneic mouse thymus of tolerant animals.
authors.affiliation: Department of Surgery, University of Pittsburgh, PA 15261.
authors.forename: S M
authors.initials: SM
authors.lastname: Wren
authors.forename: M L
authors.initials: ML
authors.lastname: Hronakes
authors.forename: S T
authors.initials: ST
authors.lastname: Ildstad
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D002454:Cell Differentiation / Q000235:genetics; D002678:Chimera / Q000235:genetics / Q000502:physiology*; D005434:Flow Cytometry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051381:Rats; D011916:Rats, Inbred F344; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte