Vaccination of pregnant cows with EspA, EspB, γ-intimin, and Shiga toxin 2 proteins from Escherichia coli O157:H7 induces high levels of specific colostral antibodies that are transferred to newborn calves

Abstract

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of intestinal disease and hemolytic uremic syndrome, a serious systemic complication that particularly affects children. Cattle are primary reservoirs for EHEC O157:H7 and the main source of infection for humans. Vaccination of cattle with different combinations of bacterial virulence factors has shown efficacy in decreasing EHEC O157:H7 shedding. It is, therefore, important to demonstrate whether vaccination of pregnant cows with EHEC O157:H7 induces high titers of transferable antibodies to avoid early colonization of calves by the bacteria. In this study we evaluated the ability of EspA, EspB, the C-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C₂₈₀) and inactivated Shiga toxin (Stx) 2 proteins to induce specific antibodies in colostrum and their passive transference to colostrum-fed calves. Friesian pregnant cows immunized by the intramuscular route mounted significantly high serum and colostrum IgG responses against EspB and γ-intimin C₂₈₀ that were efficiently transferred to their calves. Antibodies to EspB and γ-intimin C₂₈₀ were detected in milk samples of vaccinated cows at d 40 postparturition. Significant Stx2-neutralizing titers were also observed in colostrum from Stx2-vaccinated cows and sera from colostrum-fed calves. The results presented showed that bovine colostrum with increased levels of antibodies against EHEC O157:H7 may be obtained by systemic immunization of pregnant cows, and that these specific antibodies are efficiently transferred to newborn calves by feeding colostrum. Hyperimmune colostrum and milk may be an alternative to protect calves from early colonization by EHEC O157:H7 and a possible key source of antibodies to block colonization and toxic activity of this bacterium.

Immune Response in Calves Vaccinated with Type Three Secretion System Antigens and Shiga Toxin 2B Subunit of Escherichia coli O157:H7

“…Calves bearing maternal and acquired antibodies against Stx1 and in lesser extent, Stx2 [64] have been reported, sometimes with high frequency of reacting animals [65]. These antibodies have also been detected in natural bovine colostra [66] and in cows immunized with Stx2 [22, 23]. No anti Stx2 response was observed after experimental infection of calves with E .…”

Strain-Dependent Cellular Immune Responses in Cattle following Escherichia coli O157:H7 Colonization

“…In support of this hypothesis, vaccination of sows with intimin has been shown to reduce the level of EHEC O157:H7 colonization of suckling piglets (24), presumably through antibody-mediated blocking of bacterial binding. In addition, bovine colostrum has been shown to reduce T3SS-mediated hemolysis in vitro (25), and passive transfer of EspB, intimin, and neutralizing antibodies against Stx2 to calves has been demonstrated following maternal vaccination (26). H7 flagellin has also been demonstrated to act as an adhesion factor, and anti-H7 antibodies reduce the level of binding of bacteria to primary cell cultures (27).…”

The intranasal vaccination of pregnant dams with Intimin and EspB confers protection in neonatal mice from Escherichia coli (EHEC) O157:H7 infection

“…The recombinant protein EspB and the carboxyl-terminal 280 amino acid fragment of ␥-intimin ( ␥-Int C 280) were used as immunogens in combination with the macrophage-activating lipopeptide-2 (MALP-2) adjuvant [23,24]. Fig.…”