The bird’s immune response to avian pathogenic Escherichia coli

Abstract

Avian pathogenic Escherichia coli (APEC) cause colibacillosis in birds, a syndrome of severe respiratory and systemic disease that constitutes a major threat due to early mortality, condemnation of carcasses and reduced productivity. APEC can infect different types of birds in all commercial settings, and birds of all ages although disease tends to be more severe in younger birds likely a consequence of an immature immune system. APEC can act as both primary and secondary pathogens, with predisposing factors for secondary infections including poor housing conditions, respiratory viral and Mycoplasma spp. infections or vaccinations. Controlled studies with APEC as a primary pathogen have been used to study the bird's immune response to APEC, although it may not always be representative of natural infections which may be more complex due to the presence of secondary agents, stress and environmental factors. Under controlled experimental conditions, a strong early innate immune response is induced which includes host defence peptides in mucus and

Escherichia coli O88 induces intestinal damage and inflammatory response through the oxidative phosphorylation and ribosome pathway in Pekin ducks

“…The sIgA secreted by epithelial immune cells has an immunoprotective function and is considered the first line of defense in mucosal immunity ( Li et al., 2020 ). Our study showed that E. coli attacked the immune system by decreasing serum immunoglobulins and interfering with the secretion of jejunum sIgA, which is consistent with another E. coli infection study ( Alber et al., 2021 ).…”

Aerosol vaccination of chicken pullets with irradiated avian pathogenic Escherichia coli induces a local immunostimulatory effect

“…Generally, the current knowledge about the immune response against APEC is limited as there are only few studies which primarily focused on bacteriological and histopathological examinations of the affected organs such as lung and changes of antibody levels ( 12 ). The immunological basis of protection against APEC as a primary pathogen is described in the current literature which revealed that a pro-inflammatory response and cellular innate immune response play a role in this context ( 13 ). Previous transcriptome studies analysing lung, bone marrow, thymus, bursa, spleen or blood derived leukocytes showed an important function of the innate immune response to APEC ( 14 – 16 ).…”

“…Previous transcriptome studies analysing lung, bone marrow, thymus, bursa, spleen or blood derived leukocytes showed an important function of the innate immune response to APEC ( 14 – 16 ). As it was reviewed before, in regard to cellular innate immunity, heterophils, macrophages, dendritic cells and thrombocytes are described to be important in the defense against APEC ( 13 ). Innate immune cells recognize distinct pathogen-associated molecular pattern (PAMP) on the bacterial surface, which in turn activates intracellular signaling pathways resulting in antimicrobial activities and the production of pro- and anti-inflammatory cytokines.…”

Broiler resilience to colibacillosis is affected by incubation temperature and post-hatch feeding strategy

“…The difference in resilience to local E. coli infection between feeding strategies may also be the result of a difference in inflammatory response. The inflammatory response seems to play a larger role in the susceptibility to colibacillosis compared to the adaptive immune response as differences in susceptibility are for instance not related to maternal antibodies ( Ask et al, 2006b ; Ariaans et al, 2008 ; Dwars et al, 2009 ; Peng et al, 2018 ; Alber et al, 2021 ). As indicated in the previous paragraph, early fed broilers may show lower inflammatory responses compared to delayed fed broilers.…”