Recombinant Iss as a Potential Vaccine for Avian Colibacillosis

Abstract

Avian pathogenic Escherichia coli (APEC) cause colibacillosis, a disease which is responsible for significant losses in poultry. Control of colibacillosis is problematic due to the restricted availability of relevant antimicrobial agents and to the frequent failure of vaccines to protect against the diverse range of APEC serogroups causing disease in birds. Previously, we reported that the increased serum survival gene (iss) is strongly associated with APEC strains, but not with fecal commensal E. coli in birds, making iss and the outer membrane protein it encodes (Iss) candidate targets for colibacillosis control procedures. Preliminary studies in birds showed that their immunization with Iss fusion proteins protected against challenge with two of the more-commonly occurring APEC serogroups (O2 and O78). Here, the potential of an Iss-based vaccine was further examined by assessing its effectiveness against an additional and widely occurring APEC serogroup (O1) and its ability to evoke both a serum and mucosal antibody response in immunized birds. In addition, tissues of selected birds were subjected to histopathologic examination in an effort to better characterize the protective response afforded by immunization with this vaccine. Iss fusion proteins were administered intramuscularly to four groups of 2-wk-old broiler chickens. At 2 wk postimmunization, chickens were challenged with APEC strains of the O1, O2, or O78 serogroups. One week after challenge, chickens were euthanatized, necropsied, any lesions consistent with colibacillosis were scored, and tissues from these birds were taken aseptically. Sera were collected pre-immunization, postimmunization, and post-challenge, and antibody titers to Iss were determined by enzyme-linked immunosorbent assay (ELISA). Also, air sac washings were collected to determine the mucosal antibody response to Iss by ELISA. During the observation period following challenge, 3/12 nonimmunized chickens, 1/12 chickens immunized with 10 µg of GST-Iss, and 1/12 chickens immunized with 50 µg of GST-Iss died when challenged with the O78 strain. No other deaths occurred. Immunized chickens produced a serum and mucosal antibody response to Iss and had significantly lower lesion scores than nonimmunized chickens following challenge, regardless of the challenge strain. This study expands on our previous report of the value of Iss as an immunoprotective antigen and demonstrates that immunization with Iss can provide significant protection of chickens against challenge with three different E. coli strains. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Recombinant Iss as a Potential Vaccine for Avian ColibacillosisAuthor ( BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sus...

Molecular profile of avian pathogenic Escherichia coli (APEC) from poultry associated with colibacillosis in Algeria

“…All these data suggests that iss may be critically important in the pathogenesis of avian colibacillosis. Several trials were done using this gene as a potential vaccine target in the protection of this infection (Lynne et al, 2006, Lynne et al, 2012.…”

Factors affecting the immunogenicity of E. coli O78 vaccine in chickens

“…Following vaccination there was a decreased mortality and carcass contamination at slaughter, increase average body weight in comparison to previous farm history (Emery et al, 2000) Vaccinated chickens had less mortalities and lower lesion scores as compared to unvaccinated control groups (Lynne et al, 2012).…”

A similaridade genética de Escherichia coli patogênica para as aves (APEC) com estirpes humanas e a resistência antimicrobiana justificam a preocupação sanitária em relação aos produtos de origem aviária?

“…Fromer et al (1994) demonstraram que uma vacina preparada com estirpe não patogênica de E. coli induziu imunidade e proteção contra estirpes homólogas e heterólogas em aves vacinadas com 14 e 21 dias de idade. Lynne et al (2012) testaram uma vacina recombinante baseada em proteínas de fusão do gene iss de E. coli e demonstraram que esta conferiu maior proteção as aves após o desafi o quando comparadas ao grupo controle.…”