Secretion of group 2 phospholipase A2 by lacrimal glands

• Published in: Investigative ophthalmology & visual science Vol. 35; no. 2; pp. 417 - 421
• Main Authors: Nevalainen, TJ, Aho, HJ, Peuravuori, H
• Format: Journal Article
• Language: English
• Published: Rockville, MD ARVO 01.02.1994; Association for Research in Vision and Ophtalmology
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Eye and associated structures. Visual pathways and centers. Vision; Female; Fluoroimmunoassay; Fundamental and applied biological sciences. Psychology; Humans; Immunoenzyme Techniques; Lacrimal Apparatus - enzymology; Male; Middle Aged; Muscles - enzymology; Phospholipases A - secretion; Phospholipases A2; Tears - enzymology; Vertebrates: nervous system and sense organs; Human; Enzyme; Tear; Secretion; Exploration; Esterases; Experimental study; Phospholipase A; Antimicrobial agent; Carboxylic ester hydrolases; Eye; Lacrimal gland; Enzymatic activity; Hydrolases; Antibacterial agent; Localization; Lacrimal apparatus
• ISSN: 0146-0404; 1552-5783

Tears are known to have antimicrobial properties. The authors investigated the presence of the antibacterial enzyme phospholipase A2 (PLA2) in tears and lacrimal glands. The catalytic activity of PLA2 and the amount of pancreatic group 1 PLA2 and nonpancreatic group 2 PLA2 were measured in homogenates of eight human lacrimal glands from autopsied subjects and in tears from four healthy volunteers. The localization of PLA2s in lacrimal gland sections was studied by immunohistochemistry. Skeletal muscle was used as a control. The catalytic activity of PLA2 was significantly higher in lacrimal glands than in skeletal muscle. Immunochemical analysis showed significantly higher amounts of group 2 PLA2 in lacrimal gland than in skeletal muscle homogenates. Group 1 PLA2 was present in trace amounts only. The concentration of group 2 PLA2 in tears was high (1451.3 micrograms/l) compared to that in the serum of healthy individuals (3.7 micrograms/l). By immunohistochemistry, a granular reaction of group 2 PLA2 was localized in the glandular cells of lacrimal glands. The apical cytoplasm of many duct cells also was labeled. The lacrimal glands secreted nonpancreatic group 2 PLA2, which most likely acts as an antiinfectious factor in tears.