T Cell Recognition of Lysozyme. II. Shift in Specificity During Long-Term Culture Determined by Synthetic Overlapping Peptides Comprising the Entire Protein Chain

Abstract

Recently, by using a comprehensive synthetic strategy developed in this laboratory, we localized four sites (T sites) within the polypeptide chain of lysozyme recognized by T cells from two high responder mouse strains, DBA/1 and B10.BR. However, to detect minor specificities, the selective enrichment of lysozyme reactive cells, would be required. T cells from long-term cultures maintained by repeated stimulation with antigen are selectively enriched for that antigen. It is not known whether maintaining T cells for extended periods of time in vitro has any consequences on the profile of T cell recognition. In the present study, T cells from long-term cultures, derived from these two high responder lysozyme-primed mouse strains, were examined for their responsiveness to a series of synthetic overlapping peptides encompassing the entire polypeptide chain of the lysozyme molecule. We have found that the profile of T cell recognition of the long-term cultures may not reflect that of the lysozyme primed lymph node cells, but that it is subject to a shift in specificity towards submolecular features of the molecule. In addition, we have identified in B10.BR mice another region within the polypeptide chain of lysozyme (residues 72–84) which may potentially harbor a previously undetected (in lymph node cells) minor T site.