A self peptide naturally presented by both H-2K and H-2K molecules demonstrates MHC restriction of self tolerance at the molecular level.

An alloreactive CTL clone, 27.B2, produced in the mouse strain combination B6.C-H-2 (bm1) against C57BL/6 (B6) and nominally directed against the K molecule has been shown to be peptlde dependent. The clone recognizes intact B6, but not intact bm1 or bm3 target cells. However, peptides recognized by 27.B2 CTL can be extracted from bm1 or B6 whole cell lysates as well as from purified K or K molecules. The target peptides recognized by 27.B2 appear to be Identical, whether isolated from K or K-expressing cells, as shown by identical behavior upon high-resolution reversed-phase HPLC separation. Thus, the same peptlde is presented by different MHC molecules including K and K, but is recognized by 27.B2 CTL only in the context of the foreign molecule, K, and not in the context of the self molecule, K. [ABSTRACT FROM PUBLISHER]