WHile I haven't read the papers that D. Forsdyke has suggested I seem to
remember that the MHC molecules were used at some point in the past as a
compatability systems for recognizing sameness. If that is true (was
it some kind of marine organism?) the subsequent use of the machinery to
present 'foreign' peptides to Tcells would necessarily also include the
presentation the 'self' peptides.
Another aspect is the role of presentation of self peptides for the
establishment and maintainence of tolerance by deletion.
Another aspect of this is what are antigen presenting cells? Do all of
these cells work the same way? the simple answer is no since b cells and
macs are much worse than dendritic cells.
