Development of a tissue culture model for gonococcal invasion.

Neisseria gonorrhoeae invasion of the human endometrial cell line HecIB was monitored by electron microscopy. Within six hours postinfection, the gonococci have attached to the surface of some HecIB cells and are embraced by microvilli. Gonococci subsequently enter the HecIB cells in membrane bound vesicles but by eight hours, gonococci can be seen free in the cytoplasm. At twelve hours post-infection some HecIB cells are observed containing hundreds of internalized bacteria. At twenty-four hours gonococci appear in large clusters embedded in a matrix of cellular debris, which are possibly the remains of lysed infected cells. In contrast, N. lactamica is adherent to the monolayer but noninvasive.