Phagocytic activity in the retinal pigment epithelium of the frog Rana pipiens: II. Exclusion of Sarcina subflava

Abstract

In Rana pipiens embryos, tadpoles, and frogs, the ability of the pigment epithelium (PE) to phagocytize pasteurized bacteria ( Sarcina subflava ) was evaluated. The bacteria carcasses were injected into the space bounded by the retina and PE. Eyes were recovered at several intervals after injection and the location of the bacteria was determined. In each of the stages examined, phagocytic cells, probably leukocytes, invade the space between the retina and PE. Although most of the bacteria are engulfed by these invading phagocytic cells, numerous extracellular bacteria were observed in close association with the PE. Bacteria were never observed inside the PE cells, indicating that the PE failed to phagocytize this material.