HLA-DR-, MB- and novel DC-related determinants restrict purified protein derivative of tuberculin (PPD)- stimulated human T cell proliferation

Abstract

Class II major histocompatibility complex determinants restricting recognition of tuberculin antigens (purified protein derivative; PPD) were studied by using mono‐ clonal antibodies (mAb) to block lymphoproliferative responses. Anti‐class I1 mAb were shown to exert inhibitory effects at the level of the antigen‐presenting cells, without inducing suppressive lymphocytes or macrophages. Using panels of HLA‐ typed antigen‐presenting cells and nonalloreactive proliferative T cell lines, derived by limiting dilution, restriction elements for PPD responses appeared to correlate with the donor's HLA‐DRw6 specificity (one clone), MB1 (one clone), MB3 (one clone), or no established class II (or class I) specificity (three clones). mAb TÜ22, reacting with nonpolymorphic DC‐like determinants, strongly inhibited stimulation of all clones except that restricted by DR antigens, suggesting the DC‐like character not only of the MB1‐ and MB3‐associated, but also of the unassigned, restriction elements of these cloned lines. In contrast, stimulation of the DR‐restricted line was strongly inhibited by DWSB‐specific mAb which only weakly inhibited the stimulation of clones restricted by DC‐like determinants. These results suggest that clonally distributed PPD‐reactive proliferative lymphocytes from a single donor may be restricted by at least three different class Il determinants (HLA‐DR, MB, or a second, novel, DC‐related molecule).