Use of Antibody Responses against Locus of Enterocyte Effacement (LEE)-Encoded Antigens To Monitor Enterohemorrhagic Escherichia coli Infections on Cattle Farms

Abstract

dEnterohemorrhagic Escherichia coli (EHEC) is a significant zoonotic pathogen causing severe disease associated with watery and bloody diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome (HUS) in humans. Infections are frequently associated with contact with EHEC-contaminated ruminant feces. Both natural and experimental infection of cattle induces serum antibodies against the LEE-encoded proteins intimin, EspA, EspB, and Tir and the Shiga toxins Stx1 and Stx2, although the latter are poorly immunogenic in cattle. We determined whether antibodies and/or the kinetics of antibody responses against intimin, Tir, EspA, and/or EspB can be used for monitoring EHEC infections in beef cattle herds in order to reduce carcass contamination at slaughter. We examined the presence of serum antibodies against recombinant O157:H7 E. coli intimin EspA, EspB, and Tir during a cross-sectional study on 12 cattle farms and during a longitudinal time course study on two EHEC-positive cattle farms. We searched for a possible correlation between intimin, Tir, EspA, and/or EspB antibodies and fecal excretion of EHEC O157, O145, O111, O103, or O26 seropathotypes. The results indicated that serum antibody responses to EspB and EspA might be useful for first-line screening at the herd level for EHEC O157, O26, and most likely also for EHEC O103 infections. However, antibody responses against EspB are of less use for monitoring individual animals, since some EHEC-shedding animals did not show antibody responses and since serum antibody responses against EspB could persist for several months even when shedding had ceased.

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

“…On the other hand, a humoral response against EspB has been observed after vaccination, as mentioned previously, and in cattle after natural [21, 27, 52] as well as experimental infections [27, 29, 53] and in human patients suffering from HUS [53], although it is less antigenic than Intimin.…”

“…Furthermore, Intimin has strong antigenic determinants and it has been shown to be a target of humoral immune responses in different host species and animal models such as humans [47, 48], cattle [21, 29, 32, 34, 35], rabbits [49], pigs [50] and mice [51]. Antibodies against this protein have also been described after experimental (Bretschneider et al[20] as well as natural infections [21, 27, 52]. …”

Potential immunosuppressive effects of Escherichia coli O157:H7 experimental infection on the bovine host

“…In contrast, 87.5% of the animals showed a serum antibody response against Escherichia coli secreted protein B (EspB) at the same time that their faecal sample was positive for EHEC O157, O26 or, O111 or 6 weeks after a positive faecal sample. These antibodies persisted, even when shedding had ceased, until the animals were slaughtered, which was 2–8 months later, whereas EspA-specific antibodies disappeared within 2 months [9]. These results indicate that farm animals, which develop an immune response after infection, can become reinfected by different EHEC strains as evidenced by intermittent excretion which may reflect suppression of certain pathways of the immune system by the primary infection, making cattle more prone to persistent colonization by a subsequent infection.…”

Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B

“…Considering that EspB can be found in EPEC and EHEC, both related to severe diarrhea cases in human, its diagnosis and prevention are of great value for public health. Besides, since cattle are a natural reservoir of EHEC and a source for human infection, veterinary diagnosis and prevention are of major importance as well ( 37 , 38 ). Vaccine strategies to prevent EPEC and EHEC infections employing EspB as an antigen have been proposed in mice and cattle, contemplating the veterinary field ( 18 , 23 – 25 ).…”