The role of fibroblasts in thymocyte-positive selection.
Mice with fibroblast-specific expression of TAP-1 were generated by expressing the TAP-1 transgene under the control of the fibroblast-specific protein (FSP) 1 promoter/enhancer on TAP-1-deficient background. MHC class I expression in primary fibroblast cultures isolated from the resulting strain mimicked that of wild-type counterparts. MHC class I was detected in both types of fibroblasts following treatment with IFN-alphabeta. Positive selection of CD4(-)CD8(+) thymocytes was observed in neither adult nor fetal/neonatal thymus of transgenic mice. IFN-alphabeta-induced expression of MHC class I rescued positive selection of CD4(-)CD8(+) T cells in fetal thymic organ cultures, but not in adult mice. Contrary to previous suggestions, our results indicate a limited role of fibroblasts in promoting positive selection. In addition, the results suggest that positive selection may occur by a different mechanism in fetal vs adult thymus.
Lilić
Mirjana
M
Department of Pathology, Michael Heidelberger Division of Immunology and Kaplan Comprehensive Cancer Center, New York University School of Medicine, New York 10016, USA.
Santori
Fabio R
FR
Neilson
Eric G
EG
Frey
Alan B
AB
Vukmanović
Stanislav
S
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D005333:Fetus; D005347:Fibroblasts / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D015870:Gene Expression / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009924:Organ Culture Techniques; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D019076:Transgenes / Q000276:immunology; D015854:Up-Regulation / Q000276:immunology
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D015395:Histocompatibility Antigens Class I; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse