Effects of polynucleotides and levamisole on alveolar macrophage morphology and receptor activity

Incubation of rabbit pulmonary alveolar macrophages in vitro with polyinosinic acid-polycytidylic acid [poly(I-C)] or levamisole results in enhanced immunoglobulin G receptor activity in comparison to untreated cells. Electron microscopy of cells treated with levamisole or poly(I-C) revealed mitochondrial swelling and cytoplasmic vacuolization. The modulation of receptor activity by these agents suggests that their immunopotentiating effects are due to direct stimulation of the mononuclear phagocyte system. Lavaged alveolar macrophages have the capacity to change membrane function in vitro, and these cells provide a convenient system for studying agents with potential effects on macrophages.