A “New” Primed Lymphocyte Typing (PLT) Defined DP-Antigen Associated with a Private HLA-DR Antigen

Abstract

Recently a new private HLA-DR antigen, DR "LTM", which has a frequency of approximately 0.6% in Danes was described. Primed Lymphocyte Typing (PLT) cells directed towards DR "LTM"-associated determinants were generated in vitro by haplotype primings in 2 unrelated families with DR "LTM"-positive individuals. Both PLT cells reacted in parallel and gave positive reactions with unrelated and related individuals, all of whom were DR "LTM"-positive. Both PLT cells gave negative reactions with 38 unrelated and 15 related DR "LTM"-negative individuals. There was total agreement between the results obtained by HLA-DR typing with the antiserum "LTM" and by PLT-typing with these 2 haplotype-primed PLT cells. None of the DP" LTM"-positive individuals carried more than 1 of the antigens HLA-Dw/DRw/DP1-8 and the local specificity D/DP "H". This new PLT-defined antigen, DP "LTM", most probably belongs to the series of HLA-D/DR-associated DP-antigens previously described.