Development of T cells in SCID mice grafted with fetal thymus from AKR mice or F344 rats.
To examine the development of T cells within an allogeneic or xenogeneic environment, we engrafted the fetal thymus from AKR mice or F344 rats under the kidney capsule of SCID mice (mTG and rTG mice). T lymphopoiesis developed in SCID mice 2 months after transplantation, although the ratio of CD4/CD8 in both experimental groups was different from that of normal control. T cells in mTG mice did not show in vitro proliferation or cytotoxicity against either host-type C.B-17 (H-2d) or donor-type AKR (H-2k) cells, while they exerted potent activities against third-party B10 (H-2b) cells. In contrast, T cells in rTG mice exhibited proliferation against both host-type C.B-17 and donor-type F344 rat cells. Consistently, graft-vs.-host disease symptoms developed in these mice and histological examination showed impressive infiltration of lymphocytes into the skin or into the mucosal layers of the stomach. Activated state of T cells in rTG mice was also evidence by the positive expression of interleukin-2 receptor. Taken together, fetal thymus appears to contain progenitor cells which are sufficient for in vivo reconstitution of T lymphopoiesis, but species-specific environment is important for the induction of tolerance. In mTG mice, V beta 6+ T cells reactive to donor Mlsa determinants and V beta 3+ T cells reactive to host Mlsc determinants were deleted, suggesting that tolerance was regulated mainly by clonal deletion. By contrast, V beta 11+ T cells reactive to Mlsf determinants were not deleted possibly due to the lack of their ligands.
Maeda
K
K
Department of Parasitology and Immunology, School of Medicine, University of Tokushima, Japan.
Nagasawa
H
H
Furukawa
A
A
Hisaeda
H
H
Maekawa
Y
Y
Manabe
T
T
Kudo
E
E
Good
R A
RA
Himeno
K
K
D000818:Animals; D017637:Clonal Deletion; D006086:Graft vs Host Disease / Q000209:etiology; D006410:Hematopoiesis; D008213:Lymphocyte Activation; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D010641:Phenotype; D051381:Rats; D011916:Rats, Inbred F344; D018089:Superantigens / Q000276:immunology; D013601:T-Lymphocytes / Q000502:physiology*; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology; D013950:Thymus Gland / Q000196:embryology / Q000637:transplantation*; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous
D018089:Superantigens