Intrathymic lymphopoiesis: stromal cell-associated proliferation of T cells is independent of lymphocyte genotype.
We analyzed the genetic restriction of direct cell-cell interactions between thymocytes and a) cortical epithelial cells, b) macrophages, and c) medullary dendritic cells in the mouse thymus. Thymectomized (C3H X C57BL/Ka)F1 hybrid mice were doubly grafted with P1 and P2 neonatal thymus grafts, were lethally irradiated, and were reconstituted with a mixture of P1 and P2 bone marrow cells which differed in the Thy-1 locus. The contributions of both parental inocula to the composition of the free and stromal cell-associated T cell compartments were analyzed separately in thymic grafts of each parental strain. The lymphoid composition in both compartments essentially reflected the peripheral T cell-chimerism in the host. The development of lymphostromal complexes was not restricted by the genotype of the partner cells. Statistical analysis of the distributions of P1 and P2 T cells among free thymocytes and within individual lymphostromal complexes, however, suggests that the T cells of an individual complex are the progeny of oligoclonal proliferation. Thus, both epithelial cells and bone marrow-derived stromal cells seem to be involved in different stages of intrathymic lymphopoiesis.
D000818:Animals; D002450:Cell Communication; D002453:Cell Cycle; D004847:Epithelial Cells; D005260:Female; D005838:Genotype; D006183:H-2 Antigens / Q000235:genetics*; D006410:Hematopoiesis; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology*
D006183:H-2 Antigens