FIG. 1.

Electron micrographs demonstrating the attachment and internalization of streptococci by human cultured pharyngeal cells. Group A streptococci were observed to associate with microvilli upon initial contact with the pharyngeal cells. Membrane extension occurred during the internalization process. Surface interaction can be seen between the pharyngeal cell and streptococcus. Intracellular streptococci were found ingulfed in cytoplasmic vacuoles. Magnifications: A, ×12,700; B, ×24,300. (Reprinted from reference 187 with permission from the publisher.)