We investigated the expression of immunoglobulin A (IgA) in porcine salivary glands and saliva, and its relation with restraint stress in pigs. IgA was expressed in plasma cells in pig salivary glands, as confirmed by immunohistochemical staining. Interestingly, the number of IgA-positive plasma cells was different among 3 kinds of salivary glands. An enzyme-linked immunosorbent assay also detected the presence of IgA in pig saliva itself, and restraint stress was found to increase salivary IgA levels. Moreover, IgA production exhibited a circadian rhythm over the course of a day. These results are the first evidence showing that IgA expression in the pig saliva is related to stress, and may prove IgA useful as a non-invasive biological marker to evaluate acute stress conditions in pigs.
(Research Team for Advanced Biologicals)
References:
Muneta Y. et al. (2010) J. Vet. Med. Sci. 72 (10): 1295-1300
