CROSS-REACTIVITY OF HUMAN NICKEL-REACTIVE T-LYMPHOCYTE CLONES WITH COPPER AND PALLADIUM

Twenty Ni-reactive T-lymphocyte clones were obtained from eight differ ent donors and analyzed for their ability to cross-react with other me tals. All Ni-reactive T-lymphocyte clones were CD4(+)CD8(-) and recogn ized Ni in association with either HLA-DR or -DQ molecules. Based on t he periodic table of the elements, the metals Cr, Fe, Co, Cu, and Zn f rom the same horizontal row as Ni, and Pd and Pt from the same vertica l row, were selected to study T-lymphocyte clone cross-reactivity. Dis tinct cross-reactivity patterns were found that could be divided into three major groups: Ni-reactive T-lymphocyte clones i) cross-reacting with Cu, ii) cross-reacting with Pd, or iii) without cross-reactivity. Major histocompatibility complex class II-restriction patterns of Cu- and Pd-induced proliferative responses did not differ from those for the Ni-induced responses, In vitro crossreactivities with Cu and Pd ma y be favored by their bivalency and location next to Ni in the periodi c table, and the similarity of these metals to Ni in binding to histid ine residues of peptides in the pocket of major histocompatibility com plex class II molecules, The present findings suggest that Cu and Pd h ypersensitivities, which are occasionally observed in Ni-allergic pati ents, may be due to cross-reactivities at the T-cell clonal level rath er than to concomitant sensitization.