Cutting edge: TCR alpha beta+ CD8 alpha alpha+ T cells are found in intestinal intraepithelial lymphocytes of mice that lack classical MHC class I molecules.
TCR alpha beta+ intestinal intraepithelial lymphocytes (IEL) can express either the typical CD8 alpha beta heterodimer or an unusual CD8 alpha alpha homodimer. Both types of CD8+ IEL require class I molecules for their differentiation, since they are absent in beta2m-/- mice. To gain insight into the role of class I molecules in forming TCR alpha beta+ CD8+ IEL populations, we have analyzed the IEL in mice deficient for either TAP, beta 2m, CD1, or K and D. We find that K-/-D-/- mice have TCR alpha beta+ CD8 alpha alpha+ IEL, although they are deficient for TCR alpha beta+ CD8 alpha beta+ cells. This indicates that at least some TCR alpha beta+ CD8 alpha alpha+ IEL require only nonclassical class I molecules for their development. Surprisingly, the TCR alpha beta+ CD8 alpha alpha+ IEL are significantly increased in K-/-D-/- mice, suggesting a complex interaction between CD8+ IEL and class I molecules that might include direct or indirect negative regulation by K and D, as well as positive effects mediated by nonclassical class I molecules.
Gapin
L
L
Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA.
Cheroutre
H
H
Kronenberg
M
M
D000818:Animals; D016827:CD8 Antigens / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D006183:H-2 Antigens / Q000235:genetics* / Q000502:physiology; D064532:Histocompatibility Antigen H-2D; D016130:Immunophenotyping; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis* / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000378:metabolism*
D016827:CD8 Antigens; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D016693:Receptors, Antigen, T-Cell, alpha-beta