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DR beta peptides block the antigen-specific response but not the alloresponse of a dual-reactive T-cell clone
R G Ulrich1, J W Thomas, G G Miller
1Department of Microbiology, Baylor College of Medicine, Houston, TX 77030.
It is generally assumed that alloreactivity and the response to foreign antigens are equivalent T-cell recognition events. We have addressed this issue by examining the antigen presentation of beef insulin by two DR1-restricted human T-clones. One of the clones was dual-reactive and exhibited alloreactivity. By employing 20 synthetic consecutive overlapping peptides representing the entire extracellular (residues 1-198) and intracellular (residues 222-273) parts of the DR2 beta molecule, the effects of each of these peptides on antigen presentation and alloreactivity were examined. The DR1-restricted response to beef insulin by both clones was inhibited by peptides from DR2 beta region 1-25. Other DR2 beta (residues 21-198 en 222-237) or control peptides had no effect. The DR3-associated alloresponse of the dual-reactive clone was not inhibited by any peptide. These observations suggest that recognition of antigen is fundamentally different from allorecognition.
It is generally assumed that alloreactivity and the response to foreign antigens are equivalent T-cell recognition events. We have addressed this issue by examining the antigen presentation of beef insulin by two DR1-restricted human T-clones. One of the clones was dual-reactive and exhibited alloreactivity. By employing 20 synthetic consecutive overlapping peptides representing the entire extracellular (residues 1-198) and intracellular (residues 222-273) parts of the DR2 beta molecule, the effects of each of these peptides on antigen presentation and alloreactivity were examined. The DR1-restricted response to beef insulin by both clones was inhibited by peptides from DR2 beta region 1-25. Other DR2 beta (residues 21-198 en 222-237) or control peptides had no effect. The DR3-associated alloresponse of the dual-reactive clone was not inhibited by any peptide. These observations suggest that recognition of antigen is fundamentally different from allorecognition.