Expression and function of bovine CCL28 (98.28)

Abstract

Bovine mastitis represents the most costly disease of the dairy industry. In an effort to better understand natural host defense mechanisms against mastitis causing pathogens we have begun to characterize the bovine chemokine CCL28 (bCCL28). CCL28 is a dual function chemokine which has been shown to mediate migration of antibody secreting cells to mucosal tissues; this chemokine has also been shown to function as an antimicrobial protein. We have found that expression of bCCL28 mRNA in bovine mucosal tissues is highly variable with highest expression in exocrine glands, including mammary gland and milk. Additionally, we demonstrate that recombinant bCCL28 has antimicrobial activity against mastitis causing microorganisms, including Staphylococcus aureus, Streptococcus uberis, and Streptococcus agalactiae. These results demonstrate that bCCL28 is expressed in mucosal tissues and exhibits potent antimicrobial activity in vitro, suggesting that this dual function chemokine may serve an important role in bovine immunity.