Immunologic Reactivity to Viral Antigens in Chickens Infected With Avian Leukosis Viruses

Summary

The immunologic response to viral antigens of chickens rendered tolerant to a subgroup A avian leukosis virus, ALV-F42, was investigated. Attempts to break tolerance by the challenge with a related virus, RAV-1, were, with one exception, unsuccessful. Antibody responses to immunization with influenza virus in control and tolerant birds of various ages indicated that there was no impairment of the ability of tolerant birds to respond to this virus. In contrast, challenge of chickens tolerant to subgroup A avian leukosis virus with subgroup B avian leukosis virus, RAV-6, revealed an age-dependent suppression of antibody response to RAV-6. There was evidence that double infection with ALV-F42 and RAV-6, but not infection with either ALV-F42 or RAV-6 alone, led to some general suppression of antibody response, as measured by reduced influenza antibody titers after challenge with influenza virus.