Studies on the phagocytic capacity of macrophage polykaryons.

Following the demonstration by Chambers (1977a,b and c) that simultaneous attachment of macrophages to endocytogenic material in vitro leads to fusion, as analysis of the phagocytic potential of giant cells has provided evidence that the same mechanism is operating in macrophage polykaryon formation in vovo. Unlike previously proposed models for macrophage fusion, fusion by simultaneous attempted endocytosis is associated with the interiorisation of surface membrane during fusion. This has been shown to have occurred during glass coverslip-induced fusion in vivo. Evidence has also been presented that it is the endocytogenic material produced in the granulomatous environment which leads to fusion, not necessarily the simulaneous attempted endocytosis of the implanted foreign material.