Bovine myeloid antimicrobial peptide-28 (BMAP-28) mRNA expression by bovine cells and effects of synthetic MAP-28 on bovine respiratory disease pathogens

Mannheimia haemolytica (MH) is the principal bacterial patho­gen associated with bovine respiratory disease (BRD) in beef cattle. Bovine Herpes virus type 1 (BHV-1) can cause BRD by itself or it can predispose cattle to BRD due to MH or other op­portunistic bacteria. Existing antimicrobials do not consis­tently prevent BRD due to MH, and do not have an effect against viruses; bovine antimicrobial peptides (AMP) have immune stimulating and nonspecific antimicrobial effects that could improve BRD control. Messenger RNA (mRNA) treatment could be used to induce AMP expression in cattle, but efficacy must first be confirmed in vitro. Synthetic AMP can be generated to use as standards when characterizing mRNA-expressed AMP. We hypothesized that bovine cells can express synthetic mRNA coding for the AMP BMAP-28 and that synthetic BMAP-28 can inhibit the growth of MH and elicit antiviral effects against BHV-1 virus.