Regional differences in phagocytosis by the corneal endothelium in the domestic cat.

The phagocytosis of IgG-coated latex microspheres by the central and peripheral regions of the corneal endothelium in the domestic cat was investigated by organ culture. The endothelium was exposed to 1.357 X 10(7) microspheres/mm2, and counts of ingested microspheres were made by scanning electron microscopy. Initial assessments of phagocytosis over 8-h and 24-h periods of culture gave extremely low levels of incorporation. Therefore, subsequently, a 48-h period of culture was adopted. Microsphere uptake levels per square millimeter over 48 h were as follows: peripheral endothelium 6,021 +/- 3,162; central endothelium 2,000 +/- 1,529; overall 4,011 +/- 3,294. The greater uptake of microspheres in the peripheral cornea was statistically significant (P less than 0.002, paired t-test). The involvement of microvilli in phagocytosis by corneal endothelial cells was proposed.