EPITHELIAL ANTIBIOTIC-INDUCED IN STATES OF DISEASE

Epithelial defensins provide an active defense against the external mi crobial environment, We investigated the distribution and expression o f this class of antimicrobial peptides in normal cattle and in animals in varying states of disease, beta-defensin mRNA was found to be wide ly expressed in numerous exposed epithelia but was found at higher lev els in tissues that are constantly exposed to and colonized by microor ganisms. We observed induction in ileal mucosa during chronic infectio n with Mycobacterium paratuberculosis and in bronchial epithelium afte r acute infection with Pasteurella haemolytica. It has been proposed t hat expression of antimicrobial peptides is an integral component of t he inflammatory response, The results reported here support this hypot hesis and suggest that epithelial defensins provide a rapidly mobilize d local defense against infectious organisms.