ANTIMICROBIAL PEPTIDE EXPRESSION IS DEVELOPMENTALLY-REGULATED IN THE OVINE GASTROINTESTINAL-TRACT

Antimicrobial peptides are abundant components of the innate immune sy stem present in species throughout the plant and animal kingdoms. In m ammals, these immune peptides have been localized to epithelial tissue s of the pig, mouse, rat, cow and human gastrointestinal tracts. We ha ve identified in sheep two members of the beta-defensin antimicrobial peptide gene family that are expressed in a unique pattern throughout the gastrointestinal tract. Sheep beta-defensin 1 mRNA is the most pre valent from tongue to colon with the exception of the distal ileum, wh ere beta-defensin 2 mRNA predominates, Sheep beta-defensin expression varies significantly between animals and is developmentally regulated both pre-and postnatally, These changes in antimicrobial peptide expre ssion may correlate with anatomical differentiation as well as physiol ogic adaptations to extra-uterine life.