Ogimoto M, Yoshikai Y, Matsuzaki G, Ohga S, Matsumoto K, Nomoto K
Department of Immunology, Kyushu University, Fukuoka, Japan.
Thymus. 1991 Feb;17(1):11-22.
Kinetics of T cells bearing V beta 6 capable of recognizing Mls-1a were examined in the thymus and peripheral lymphoid organs of two allogeneic bone marrow chimeras; AKR/J(H-2k, Thy1.1,Mls-1a)----C3H/He(H-2k, Thy1.2,Mls-1b) and AKR/J----C57BL/6(H-2b,Thy1.2, Mls-1b). Sequential appearance of host- and donor-derived T cells occurred in the thymus and the peripheral lymphoid organs of both AKR----C3H and AKR----B6 chimeras. The first cells to repopulate the thymus were Thy1.2+ host-derived radioresistant cells, which were synchronized in their development. The host-derived cells in thymus of AKR----B6 chimeras differentiate more rapidly than those in AKR----C3H chimeras. An almost complete replacement from host-derived cells to donor-derived cells occurred by day 21 after reconstitution in AKR----C3H and AKR----B6 chimeras. In the donor-derived thymocytes, none of CD4- or CD8-single positive thymocytes expressed high density of V beta 6 in either AKR----C3H or AKR----B6 chimeras, whereas the host-derived thymocytes in AKR----B6 chimeras contained an appreciable number of CD4-single positive thymocytes bearing V beta 6. In the peripheral lymphoid organs, T cells bearing V beta 6 were virtually abolished in Thy1.1+ cell pool of both AKR----C3H and AKR----B6 chimeras. While V beta 6+ T cells of host-origin were detected in the peripheral lymphoid organs in AKR----B6 chimeras. These result indicated that the donor-derived mature T cells showed deletion of V beta 6 in the thymus and the peripheral lymphoid organs in both AKR----C3H and AKR----B6 chimeras, whereas lack of V beta 6 deletion was observed in the host-derived mature T cells in the AKR----B6 chimeras. These results suggested that the host-derived thymocytes may likely to escape undergoing a negative selection against donor-phenotype in the radiation bone marrow chimeras.
在两只同种异体骨髓嵌合体的胸腺和外周淋巴器官中，研究了能够识别Mls-1a的携带Vβ6的T细胞的动力学；AKR/J(H-2k,Thy1.1,Mls-1a)----C3H/He(H-2k,Thy1.2,Mls-1b)和AKR/J----C57BL/6(H-2b,Thy1.2,Mls-1b)。在AKR----C3H和AKR----B6嵌合体的胸腺和外周淋巴器官中，宿主来源和供体来源的T细胞相继出现。最早重新填充胸腺的细胞是Thy1.2+宿主来源的放射抗性细胞，它们在发育上是同步的。AKR----B6嵌合体胸腺中的宿主来源细胞比AKR----C3H嵌合体中的宿主来源细胞分化得更快。在AKR----C3H和AKR----B6嵌合体中，重组后第21天，宿主来源细胞几乎完全被供体来源细胞取代。在供体来源的胸腺细胞中，在AKR----C3H或AKR----B6嵌合体中，CD4-或CD8-单阳性胸腺细胞均未表达高密度的Vβ6，而AKR----B6嵌合体中的宿主来源胸腺细胞含有相当数量的携带Vβ6的CD4-单阳性胸腺细胞。在外周淋巴器官中，AKR----C3H和AKR----B6嵌合体的Thy1.1+细胞池中携带Vβ6的T细胞几乎被清除。而在AKR----B6嵌合体的外周淋巴器官中检测到了宿主来源的Vβ6+T细胞。这些结果表明，在AKR----C3H和AKR----B6嵌合体中，供体来源的成熟T细胞在胸腺和外周淋巴器官中均表现出Vβ6的缺失，而在AKR----B6嵌合体的宿主来源成熟T细胞中未观察到Vβ6的缺失。这些结果表明，在辐射骨髓嵌合体中，宿主来源的胸腺细胞可能逃避了针对供体表型的阴性选择。
