Appearance of TCR-alpha beta+ CD4-CD8- skin intraepithelial lymphocytes in radiation bone marrow chimeras.
Thymocytes expressing homogeneous TCR V gamma 5/V delta 1 gene without N nucleotide addition (canonical sequence) have been reported to be positively selected in fetal thymus. Because skin intraepithelial lymphocytes (s-IEL) also express canonical sequence, it is proposed that s-IEL are generated by an epidermis-specific homing of these positive selected fetal V gamma 5/V delta 1-bearing thymocytes. We have reported that positive selection of V gamma 5+ thymocytes is not seen in AKR/J-->C3H/He bone marrow chimeras. In this report, we analyzed the phenotype of donor-derived s-IEL from AKR/J-->C3H/He bone marrow chimeras that appeared in the absence of positive selection of V gamma 5-bearing thymocytes. We found interestingly that almost all donor-derived s-IEL in the bone marrow chimeras expressed TCR-alpha beta lack expression of both CD4 and CD8. Furthermore, TCR-alpha beta+ s-IEL were detected in adult-thymectomized bone marrow chimeras, indicating that the TCR-alpha beta+ s-IEL are extrathymically derived. All these results suggest that the s-IEL expressing TCR-alpha beta appear extrathymically in the absence of positive selection of V gamma 5/V delta 1-bearing thymocytes. Our results may also explain the contradicting result between human s-IEL, which are TCR-alpha beta+ CD4- CD8- and murine s-IEL, and suggest the importance of extrathymic T cell differentiation pathway of the TCR-alpha beta lineage in immune surveillance.
Ogimoto
M
M
Department of Immunology, Kyushu University, Fukuoka, Japan.
Matsuzaki
G
G
Yoshikai
Y
Y
Tauchi
Y
Y
Nomoto
K
K
D000818:Animals; D016026:Bone Marrow Transplantation / Q000276:immunology*; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D005260:Female; D008099:Liver / Q000276:immunology; D051379:Mice; D008806:Mice, Inbred AKR; D008809:Mice, Inbred C3H; D011828:Radiation Chimera; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D012867:Skin / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013934:Thymectomy
D015704:CD4 Antigens; D016827:CD8 Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta