Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 6/28/2007
Publication Date: 12/1/2008
Citation: Rath, N.C., Xie, H., Huff, W.E., Huff, G.R. 2008. Activation of macrophage and heterophil function by ovotransferrin, an avian acute phase protein. In: Muller, G.V., editor. New Immunology. New York, NY: Nova Science Publishers. p. 95-108. Interpretive Summary: Natural defense mechanism consists of many types of vigilant blood proteins and cells which kill the disease causing agents. We identified one such protein in chicken blood after artificial induction of a infection-like condition. This protein called serum transferrin is similar to a protein named ovotransferrin present in the eggs. To find its function we studied its effects on blood macrophages and heterophils, the cells that destroy bacteria. Our results show that this protein can stimulate those cells to produce factors that boost defense mechanisms.
Technical Abstract: 'Acute phase response' is an innate defense mechanism that activates a variety of cellular and humoral components including, the changes in some serum proteins called 'acute phase protein (APP).' Using avian models of experimental inflammation, induced by endotoxin and croton oil, we examined the changes in the serum proteins of chickens and found transferrin to be a major APP that was identical to ovotransferrin (OVT), an egg white protein. Using an enzyme-immunoassay, the results showed serum OVT to be elevated during a variety of bacterial and viral infections. The functional significance of OVT in relation to immunity was examined by studing its in vitro effects on avian macrophage and heterophils. The results indicate that OVT activates the functions of phagocytes as measured by the production of nitric oxide, interleukin-6, matrix metalloproteinase, and respiratory burst activity. Additionally, OVT also stimulated heterophil degranulation. These results demonstrate that beyond its antibacterial effects, the OVT may act as a natural immunomodulator enhancing innate immune function.