The influence of killed Mycobacterium leprae and other mycobacteria on opsonized yeast phagocytosis.

The influence of killed mycobacteria on the metabolic burst associated with phagocytosis of opsonized zymosan by normal human polymorphonuclear leucocytes (PMNL) or monocytes was studied by chemiluminescence (CL) measurements. M. leprae reproducibly reduced the peak and total CL of both types of phagocyte to a small, but highly significant extent. Electron microscopy showed that M. leprae were phagocytosed: cells with ingested or adherent M. leprae phagocytosed fewer zymosan particles. M. leprae did not cause aggregation of the phagocytes or quenching of CL. M. lepraemurium did not influence the CL response to zymosan. Addition of M. tuberculosis caused an increased response with PMNL but not with monocytes.