Synthesis of group II phospholipase A2 and lysozyme in lacrimal glands

Abstract

Purpose: The aim of this study was to demonstrate the synthesis and cellular distribution of group II phospholipase A2 and lysozyme in the main and accessory lacrimal glands.

Methods: The authors studied samples of normal main lacrimal glands of seven autopsied subjects and accessory lacrimal glands of eight patients who underwent ptosis surgery. The specimens were immunostained with a rabbit antiserum against group II phospholipase A2 and a monoclonal antibody against lysozyme. Expression of group II phospholipase A2 gene was shown using Northern hybridization and in situ hybridization.

Results: Lysozyme was present in the secretory granules of most acini, whereas group II phospholipase A2 was seen in a minority of acinar cells, primarily in the central parts of lobules in the main and accessory lacrimal glands. Synthesis of group II phospholipase A2 in the glandular cells was confirmed by Northern hybridization and by in situ hybridization.

Conclusions: There are two specialized cell types in the main and accessory lacrimal glands, one synthesizing group II phospholipase A2 and the other synthesizing lysozyme. These enzymes are important nonspecific antibacterial factors in tears.