Positive selection of extrathymically developed T cells by self-antigens.
Most T cells develop through the thymus, where they undergo positive and negative selection. Some peripheral T cells are known to develop in the absence of thymus, but there is insufficient information about their selection. To analyze the selection of extrathymically developed T cells, we reconstituted thymectomized male or female recipient mice with bone marrow cells of mice transgenic for male H-Y antigen-specific T cell receptor (TCR). It was revealed that the T cells bearing self-antigen-specific TCR were not deleted in thymectomized male recipients. More importantly, the absence of H-Y antigen-specific T cells in thymectomized female recipients suggests positive selection of extrathymically developed T cells by the self-antigen. The extrathymically developed T cells in male mice expressed interleukin (IL)-2 receptor beta chain (IL-2Rbeta) and intermediate levels of CD3 (CD3(int)) but were natural killer cell (NK)1.1(-). They rapidly produced interferon gamma but not IL-4 after TCR cross-linking. Furthermore, a similar pattern of cytokine production was observed in CD3(int)IL-2Rbeta+NK1.1(-) cells in normal mice which have been shown to develop extrathymically. These results suggest that extrathymically developed CD3(int)IL-2Rbeta+NK1. 1(-) cells in normal mice are also positively selected by self-antigens.
Department of Immunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan. hisako@bioreg.kyushu-u.ac.jp
H
H
Yamada
T
T
Ninomiya
A
A
Hashimoto
K
K
Tamada
H
H
Takimoto
K
K
Nomoto
D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D005260:Female; D006182:H-Y Antigen / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013934:Thymectomy; D013950:Thymus Gland
D006182:H-Y Antigen; D011948:Receptors, Antigen, T-Cell; D015847:Interleukin-4; D007371:Interferon-gamma