Innate immune response of mammary gland induced by intramammary infusion of

摘要

This study aimed to evaluate innate immune responses of mammary glands induced by intramammary infusion of Bifidobacterium breve in dairycows. Somatic cell counts in quarters of cows showed a marked increase following B. breve infusion on days 1 and 2. Opsonized-stimulatedchemiluminescence response in quarter milk was significantly (P<0.05) increased by B. breve infusion on days 1 to 3compared to that of pre-infusion. Lactoferrin concentrations in B. breve-infused quarter milk increased significantly(P<0.05) on days 2 to 4 and 6 compared to those of pre-infusion. IgG and IgA concentrations in B. breve-infused quarterssignificantly (P<0.05) increased on days 2 to 4 for IgG and days 3, 4, 6 and 8 for IgA compared to those of pre-infusion. Interleukin(IL)-1β and IL-8 mRNA levels in somatic cells from B. breve-infused quarters were significantly (P<0.05) upregulated on day1 compared to those on days 0 and 14. Conversely, IL-6 mRNA levels in somatic cells from B. breve-infused quarters on days 0, 1 and 14 andNF-κB mRNA levels on day 0 were significantly (P<0.05) down-regulated compared to those of control. IL-1β, tumor necrosisfactor (TNF)-α and IL-6 concentrations increased on days 1, 3 and 7 after B. breve infusion in quarters. Intramammary infusion of B.breve (3 × 109 cfu) induces a massive influx of leukocytes and enhances innate immune response in mammary glands. This event maycontribute to the enhancing host defense in the mammary gland.