2011 - 2014

Stimulation of innate immune system for the control of poultry respiratory viral infections

Principal Investigator: Faizal Abdul Careem, University of Calgary
Status: Completed


Microbial structural components, that are known to bind to avian immune cells, are used to stimulate innate immunity in the chicken respiratory system. The enhanced immune function is tested by challenging chickens with various respiratory viruses. The mechanisms of protection induced by these microbial components are identified, as well as any adverse effects on the chicken immune system.


Preventing disease within the poultry industry is vital for maintaining flock health, bird welfare, and food safety. Numerous methods of disease prevention are used, such as biosecurity practices, vaccinations and the use of antimicrobial medications. However, these methods are not 100% effective, may not have immediate effects, if desired and, in the case of antimicrobials, are largely under scrutiny in regards to their use and subsequent resistance in bacterial populations. Utilising the highly developed avian immune system may provide alternate disease prevention methods. Poultry immune responses can be categorized into “adaptive” and “innate” responses. Innate immunity is able recognize pathogens and clear an infection before an antigen-specific (adaptive) response can even be developed. In doing this, the avian immune system has the ability to rapidly recognize and respond to specific characteristics of invading pathogens. Dr. Faizal Careem and his research team at the University of Calgary are investigating which pathogen-derived compounds could stimulate innate immune responses in chickens, when injected into the eggs at 18 days of incubation. The immune responses could protect chickens against respiratory viruses such as infectious bronchitis virus (IBV), infectious laryngotracheitis (ILTV) and avian influenza (AI). This project is also planning to identify the mechanism of protection against these viruses, as well as any adverse effects that the mechanism may have on immune functions.


So far, the antiviral responses of two microbial components (lipopolysaccharides and lipoteichoic acid) against ILTV, and their mechanisms of protection, have been evaluated.  The team is in the process of assessing whether the protection observed against ILTV could be extended against other respiratory viruses. These microbial components will be further evaluated to identify any adverse effects on the immune function of the chickens.


Utilising the molecular compounds from microbes to stimulate innate immune responses in chickens may contribute to effective poultry disease prevention. Exposing chicks to microbial compounds in-ovo shows promise for protecting birds from viral infection once hatched, improving long-term immunity for commercial poultry. Since the work could be extended for potential bacterial disease control, the work will also aid in curbing the use of antimicrobials, leading to a reduction of resistant pathogens.


$436,000 ($60,000 CPRC, $119,700 ALMA, $200,000 U Calgary, $56,305 NSERC-RTI)


Haddadi, S., Kim, D.S., Hui, J., van der Meer, F., Czub, M., Abdul-Careem, M.F. 2013. Induction of Toll-like receptor 4 signaling in avian macrophages inhibits infectious laryngotracheitis virus replication in a nitric oxide dependent way. Veterinary Immunology and Immunopathology, 155: 270-275.  

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