Addendum

Abstract

Evidence in support of a killer role for GMG cells has emerged in a time-lapse video study of the behaviour of co-cultured GMG cells and trophoblast (Stewart and Mukhtar 1988). GMG cells migrate from expiants of mouse metrial gland (Mukhtar and Stewart 1988, p. 81) and their behaviour in relation to the presence of cells from the placental labyrinth showed clearly that some trophoblast cells died rapidly after they had been in contact with GMG cells (Stewart and Mukhtar 1988). The highly mobile GMG cells made contacts with various types of trophoblast cells but Stewart and Mukhtar’s results suggested that only cells classified by them as stellate died after being contacted by GMG cells. Only a small proportion of GMG-stellate cell interactions, however, were fatal for the trophoblast cells and GMG cell death was not seen. On the basis of histological studies of mouse placenta showing that GMG cells may be found adjacent to degenerate layer 1 labyrinthine trophoblast cells (Stewart 1984, pp. 52, 131), Stewart and Mukhtar (1988) suggested that the stellate cells in vitro may represent layer 1 trophoblast. It is pertinent to draw a parallel between the infrequency of GMG-trophoblast cell interaction associated with trophoblast cell death in vitro and in vivo and to examine the highly selective activity of GMG cells to determine why only some of their contacts with trophoblast are fatal.