The effect of neuraminidase on the aggregation of BHK21 cells and BHK21 cells transformed by polyoma virus.

Bacterial neuraminidases increase the adhesiveness in suspension of freshly trypsinized hamster fibroblasts (BHK21 cells). The effect is seen most clearly when the enzymes are added to pre-aggregated suspensions, but can also be observed when cells in monolayer culture are pre-incubated with neuraminidase, suspended, and then aggregated in its absence. BHK21 cells transformed by polyoma virus respond only very slightly to neuraminidase, which therefore increases the difference in adhesiveness between transformed and untransformed cells. Neuraminidase does not eliminate the difference in adhesiveness between sparsely and densely grown BHK21 cells. These findings are consistent both with the lyophobic colloid theory of cell adhesion and with proposals that intercellular adhesion depends on complementary molecules on the surface of interacting cells. The low adhesiveness and small response to neuraminidase of transformed cells, however, are more readily explained in terms of the latter.