Lineage fate alteration of thymocytes developing in an MHC environment containing MHC/peptide ligands with antagonist properties.
A18 TCR transgenic thymocytes which are H-2E(k) restricted and normally selected into the CD4 lineage, are exclusively selected into the CD8 lineage in an H-2(q) MHC background. CD8 T cell selection in the H-2(q) background is far more efficient than default selection of A18 CD8 cells on a CD4(-/-) H-2E(k +) background. This suggests the involvement of special selecting ligands. Analogues of the cognate peptide for A18 with antagonist properties for the A18 TCR have previously been shown to effect a lineage diversion from CD4 to CD8 in fetal thymic organ cultures and intriguingly the MHC(q) background contains unidentified natural MHC class II ligands which similarly show antagonist properties for the A18 TCR. Despite the presence of these unidentified MHC class II ligands in the H-2(q) background and their potential influence on developing A18 thymocytes, however, MHC class I molecules were essential for thymic selection of A18 CD8 T cells.
Barthlott
T
T
National Institute for Medical Research, Division of Molecular Immunology, London, UK.
Stockinger
B
B
D000818:Animals; D015496:CD4-Positive T-Lymphocytes; D019070:Cell Lineage; D006183:H-2 Antigens / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000502:physiology*; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology*
D006183:H-2 Antigens; D015395:Histocompatibility Antigens Class I; D008024:Ligands; D011948:Receptors, Antigen, T-Cell