Date of this Version
Avian infectious bronchitis (IB) is a coronavirus infection of chickens that causes respiratory disease and reproductive problems in chickens. Currently, there are vaccines that are effective against IB. However, new variants and strains of avian infectious bronchitis virus (IBV) routinely emerge. A vaccine that is not the same strain as the virus is not completely effective in protecting against other variants because the vaccine will not allow the host antibodies to completely neutralize the strain. This is a problem because it makes IB difficult to control and diagnose.
Antibody-dependent enhancement (ADE) is a phenomenon whereby non-neutralizing antibodies, or low levels of neutralizing antibodies, facilitate access into the host cell and allows either an enhanced viral infection or an increase in the severity of the clinical disease. This means the virus may create more variants that render current vaccines ineffective, created problems in diagnoses and may lead to more severity clinical disease. ADE has been found to occur with dengue virus and other viruses including some coronaviruses. This is a concern because COVID-19 is a human coronavirus and many vaccines have been developed, but variants routinely arise. ADE is thought to be a very important factor for developing new vaccines because vaccines that are not specific for a serotype could enhance viral infections. This would be the first work of looking at ADE on IBV to determine if ADE is occurring.