Expression Profiling of Innate Immune Genes in Milk Somatic Cells During Subclinical Mastitis in Crossbred Dairy Cows

ABSTRACT

Innate immune mechanism plays a key role in mammary defense, from recognition of pathogens to activation of nonspecific and specific immunity involved in elimination of pathogens. Expression profiles of innate immune response genes namely Toll like receptor 2 (TLR-2), Peptidoglycan recognition protein 1 (PGLYRP-1), Interleukin 8 receptor (IL-8 R), L-Selectin (SELL), and Osteopontin (OPN) in milk somatic cells of subclinical mastitis (SCM) affected crossbred cows were investigated under this study at transcript level using quantitative real time polymerase chain reaction (qRT-PCR). Dairy cows in mid lactation were screened for SCM using California Mastitis Test (CMT), Somatic Cell Count (SCC) and Electrical Conductivity test (EC). Based on results of SCM screening tests, crossbred cows were clustered into two groups with four Staphylococcus aureus infected SCM cows and four apparently healthy cows. The expressions levels of TLR-2, PGLYRP-1, IL-8 R, SELL, and OPN in milk somatic cells of SCM affected cows were significantly higher (p < 0.05) than healthy cows. These genes could be considered as candidate genes for innate immune response against S. aureus SCM infection.

KEYWORDS:

• Candidate gene expression
• crossbred cows
• Innate immune response
• Subclinical mastitis

Acknowledgments

The authors are thankful to the authorities of Kerala Veterinary and Animal Sciences University for providing the facilities for conducting the research. The work is part of the M.V.Sc thesis submitted by the first author to Kerala Veterinary and Animal Sciences University.