Mastitis is a critical problem in the dairy industry. However, its
treatment and prevention methods have not been established. Mammary gland
has a local immune system consisting established and innate immunity. Mammary
epithelial cells can detect bacterial components using toll-like receptors
on the cell surface. Then epithelial cells produce and secrete innate immune
factors such as beta-defensin and lactoferrin and lactoperoxidase into
the milk. ß-defensin and lactoferrin attack bacteria directly and
kill it. ß-defensin family consists several components containing
lingual antimicrobial peptide (LAP). Lactoferrin absorb iron ion, resulting
in the shortage of iron ion in the surrounding circumstances. As bacteria
need iron ion for its proliferation, lactoferrin has a role in bacteriostatic
function. Cathelicidin, one of antimicrobial peptides, is secreted by leukocytes.
Mastitis recruits a number of leukocytes in mammary gland. Therefore, cathelicidin
may be contained in milk and have important role on preventing mastitis.
However, there is limited information about function of these innate immune
factor and antimicrobial peptides in the Mammary gland. @Mastitis is induced by the physiological dondition of animals such as hormone. We reported that estrogen during estrous stage induce slight increased somatic cell count and decreased milk yields. @Mastitis is induced not only bacteral invasion into udder through teat canal but also bacterial components (lipopolysachrride, LPS etc.) transferred from inflamation site another organs such as uterus (endometritis). We reported that LPS infusion into uterus caused inflammation in the udder (Purba et al.,2020, Jaisue et al., 2022, 2023). Treatment of mastitis requires the administration of antibiotics. This requires identification of the infecting organism and selection of an appropriate antibiotic. However, it has been shown that the number of viable bacteria in milk decreases drastically during preservation after sampling (Hisaeda et al., 2016). This was found to be due to phagocytosis of neutrophils (Koshiishi et al., 2017). Therefore, we are developing a methods to suppress the function of neutrophils so that the number of live bacteria does not decrease. Research Theme
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