HLA-class II restriction of the proliferative T lymphocyte responses to nickel, cobalt and chromium compounds.

Peripheral blood mononuclear cells from nickel and/or cobalt or chromium sensitive patients were stimulated with the appropriate metal compound for 7 days in culture. The transformed blasts were separated from non-transformed small cells on Percoll density gradients. The blasts, maintained in interleukin-2 containing medium and enriched for T cells, were both antigen specific and devoid of alloreactivity. The metal compound primed T cell blasts from all patients showed a good proliferative response on restimulation with the priming compound in the presence of autologous adherent cells (AC). Analysis of HLA class II phenotypes of allogeneic AC that could serve as antigen presenting cells indicated that responsiveness of T cell blasts from most but not all patients could be explained on the basis of HLA-DR as a restricting element. We conclude that products of other class II loci (HLA-DQ and/or HLA-DP) might also serve as restricting elements for a secondary in vitro proliferative response to these metal compounds.