COILING PHAGOCYTOSIS DISCRIMINATES BETWEEN DIFFERENT SPIROCHETES AND IS ENHANCED BY PHORBOL-MYRISTATE ACETATE AND GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR

The mechanisms involved in coiling phagocytosis are not yet known, and it is not even clear whether this phenomenon is either an incidental event or a specific response. Therefore, the phagocytic uptake of Borr elia burgdorferi and other spirochetes by human monocytes in vitro was used to investigate the involvement of both sides-microbes and phagoc ytes-in coiling phagocytosis. As seen with electron microscopy, morpho logically similar Borrelia, Leptospira acid Treponema strains induced markedly different frequencies of coiling phagocytosis, The monocytes used coiling phagocytosis for both live (motile) and killed (nonmotile ) B, burgdorferi, but pseudopod coils were observed neither,vith fragm ented B, burgdorferi nor with cell-free supernatant from B. burgdorfer i cultures. Investigation of the relationship of coiling phagocytosis with other pseudopod-based cellular mechanisms revealed that the use o f bioreagents that inhibit conventional phagocytosis also inhibited co iling phagocytis but did not affect membrane ruffling. Bioreagents tha t increase membrane ruffling did not affect phagocytosis of B, burgdor feri, except for granulocyte-macrophage colony-stimulating factor and phorbol myristate acetate, which increased coiling phagocytosis select ively, These results demonstrate that coiling phagocytosis is not indu ced by microbial motility, viability, or a certain morphology and that it is not a random event. Rather, it is a selective uptake mechanism actively driven by the phagocytes, However, whether coiling phagocytos is represents an independent alternative to conventional phagocytosis or, alternatively, a fault in conventional phagocytosis remains to be determined.