Reception-mediated phagocytosis of yeast by macrophage polykarions.

1. The phagocytic capacity of polynuclear macrophages (PNM) produced by intraperitoneal implants in mice was analyzed and compared with that of the mononuclear macrophage (M luminal diameter). The ability of PNM and M luminal diameter to interiorize aldehyde-fixed Saccharomyces cerevisiae is described. 2. PNM containing two to five nuclei and M luminal diameter exhibited a similar time course of phagocytosis. The phagocytic index reached a plateau from 30 to 60 min after exposure to yeast. 3. Mannose, mannan extracted from yeast and horseradish peroxidase inhibited yeast phagocytosis by PNM and M luminal diameter subpopulations to a similar extent. 4. Amino sugars (glucosamine, N-acetylglucosamine, galactosamine and N-acetylgalactosamine) caused similar reductions in the phagocytic indices of PNM and M luminal diameter. 5. The presence of monosaccharides (glucose, galactose, fructose and mannitol) did not alter the phagocytic capacity of either type of phagocyte. 6. Neither opsonin-dependent ingestion of sheep red blood cells nor ingestion of aldehyde-fixed cells by PNM or M luminal diameter is affected by mannose, suggesting that these processes involve internalization pathways different from the mannose-hexosamine recognition system. 7. Trypsin sensitivity, temperature dependence and divalent cation requirements for PNM phagocytosis were comparable to those of the M luminal diameter. 8. The similarities of the PNM to their mononuclear precursors suggest that the mannose-hexosamine receptor was preserved after polykaryon formation.