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					     Role of lactoperoxidase in mastitis and its clinical application
                      Ming-Han Chiang and Shou-Cheng Wu
                         Department of Biotechnology, NCTU
     Mastitis is an infectious disease that may spread over a dairy herd and severely
affect the production and quality of milk. Because the symptom in cows with
subclinical mastitis is subtle, it is often ignored leaving cows without treatment.
Bacteriological sampling and milk somatic cell count (SCC) has been recommended
by the International Dairy Federation (IDF) to be a standard procedure for the
diagnosis of mastitis but not practical as a routine test. The major purpose of this
report was to test whether lactoperoxidase (LPO), a milk enzyme secreted from the
epithelial layer of mammary gland, might be overexpressed in milk of mastitis. Milk
samples selected from 46 dairy cows were separated into four groups according to
SCC as group A: <100 (n = 25), B: 100-200 (n = 6), C: 201-500 (n = 5), D: >500×103
(n = 10) cells/mL. We demonstrated that LPO was not only highly expressed in milk,
but also positively correlated with the severity of mastitis. In addition, we showed that
macrophages of somatic cells also expressed LPO as determined by RT-PCR and
immunostaining. The experiment is now in progress to analyze the significance of
LPO present in the milk using purified LPO via HPLC to conduct its anti-bacterial
activity. In summary, LPO is a novel biomarker for the diagnosis of bovine mastitis.

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