Cytokine expression pattern in milk somatic cells of subclinical mastitis-affected cattle analyzed by real time PCR

Abstract

Abstract : The expression profiles of inflammatory cytokines viz. interleukins (IL)-6, IL-8, IL-12, granulocytemacrophage-colony stimulating factor, interferon-γ and tumor necrosis factor-α in response to subclinical mastitisin indigenous cattle breed Kankrej (n = 6), Gir (Bos indicus) (n = 12) and crossbred (Bos taurus× Bos indicus) (n = 7)were investigated using quantitative real time PCR. Significant correlation (p < 0.05) was observed between totalbacterial load and somatic cell count (SCC) in all three breeds of cattle. All the cytokines were observed to beup-regulated compared to cows with healthy quarters, however, level of their expression varied among three breedsof cattle. In Kankrej most cytokines were found to be transcribed to higher levels than in other two breeds; themilk had higher load of bacteria but not so high SCC, implying that Kankrej has a higher inherent resistance againstmastitis. The results of present study indicated that mammary glands of crossbred cattle are more sensitive to bacterialinfection than indigenous breed of cattle as they elicit immune response at lower bacterial load and result into higherSCC. Research on identification of factors responsible for differentially expressed cytokines profiles and use ofcytokines as immunomodulatory tools can pave way for formulating control strategies against bovine mastitis.Keywords : cytokines, interleukins, interferon, quantitative real time PCR