The expression of HLA-DR by monocytes from black and from white donors: different requirements for protein synthesis.

Epidemiologic data indicates that blacks may be more susceptible than whites to infection by Mycobacterium tuberculosis. Resistance to the in vivo growth of Mycobacteria in mice correlates with the persistence of MHC class II expression by peritoneal macrophages. The expression of HLA-DR by human monocytes from different groups of individuals also differs. The increase in the expression of HLA-DR by monocytes that occurs upon in vitro culture was prevented by the protein synthesis inhibitor cycloheximide (CHX) in a majority of black donors. In contrast, the increase in HLA-DR expression by monocytes from the majority of white donors was unaffected.