Passive Immunity of Neonatal Calves Given Colostrum Containing E. coli 0157:H7 SRP Antibodies from an E. coli K99 Challenge

Abstract

Epitopix LLC has the first license for an E. coli 0157 vaccine in the USA that is based on use of siderophore receptors and porin proteins (SRP™) that are highly conserved across a large number of Escherichia coli isolates. Neonatal calf diarrhea is one of the leading causes of morbidity and mortality in calves. The most commonly described causative agents of acute neonatal diarrhea (scours) are Escherichia coli, coronavirus, rotavirus, and Cryptosporidium. E. coli strains of the K99 pilus type have been responsible for an estimated 25-30% of the scours related morbidity in calves during the first 3-4 days after birth, and approximately 30-50% of the scours-related mortality. Since the SRP antigens in the 0157 vaccine are highly conserved among E.coli isolates, it is hypothesized that there may be a high degree of cross-protection to non-O157:H7 species of E. coli. The goal of this study is to examine the degree of cross-protection provided by colostrum containing a known amount of E. coli O157:H7 SRP antibodies against an oral challenge of E. coli K99 as evidenced by morbidity and mortality effects in neonatal colostrum deprived calves.