T-LYMPHOCYTE-INDEPENDENT AND B-LYMPHOCYTE-INDEPENDENT FORMATION OF ALVEOLAR MACROPHAGE-DERIVED MULTINUCLEATED GIANT-CELLS IN MURINE PNEUMOCYSTIS-CARINII PNEUMONIA

Multinucleated giant cells developed in Pneumocystis carinii-diseased gene disruption mutant mice deficient in major histocompatibility comp lex class II molecules, T-cell receptor alpha beta cells, or all matur e T and B lymphocytes. These findings demonstrate lymphocyte-independe nt fusion of alveolar macrophages under morbid conditions. Pulmonary p arasite burden seems to be a decisive factor in multinucleation.