Organ transplants are rapidly rejected because T cells in the recipient attack the foreign MHC molecules on the graft. The robustness of the T cell response to histoincom-patible tissue is not understood. We found that mice have many small T cell populations with Ag receptors specific for a foreign MHC class II molecule type loaded with pep-tides from leukocytes from the graft. These T cells proliferated modestly after skin transplantation and underwent relatively weak functional differentiation compared with T cells stimulated by a vaccine. Thus, the potency of the T cell response to histoincompatible tissue is likely due to many small T cell populations responding weakly to hundreds of MHC-bound peptides from graft-derived leukocytes.
Bibliographical noteFunding Information:
This work was supported by grants awarded by the National Institutes of Health (P01 AI035296, R01 AI039614, and R37 AI027998 to M.K.J.; R01 AI106791, P01 AI035296, and U24 AI118635 to B.T.F.; F32 AI114050 to D.M.; and T32 DK007203 to A.L.B.), a grant awarded by Regenerative Medicine Minnesota (11215 TR002 to B.T.F.), and a grant awarded by the Juvenile Diabetes Research Foundation (2-2011-662 to B.T.F.).
Copyright © 2018 by The American Association of Immunologists, Inc.