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item Kapczynski, Darrell
item Tumpey, Terrence

Submitted to: Western Poultry Disease Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/14/2002
Publication Date: 5/1/2002
Citation: Kapczynski, D.R., Tumpey, T. 2002. Immune function following vaccination with an inactivated avian pneumovirus vaccine. Western Poultry Disease Conference.

Interpretive Summary: Avian pneumovirus (APV) is a recently emerged infectious disease of turkeys causing severe economic losses to the turkey industry. The disease results in poor feed conversion, increased condemnations, and mortality associated with secondary bacterial infections. Inactivated APV vaccines are commercially available to European A and B subtypes. However, no data on inactivated vaccines produced with the U.S. subtype C (APV/C) virus exist. The main objective of this study was to compare cellular immune responses of turkey lymphocytes from birds vaccinated with inactivated APV/C to either live APV/C or a lymphocyte stimulant (ConA). The results indicate differences in cellular immune responses between vaccinated and non-vaccinated groups. Birds not vaccinated, had higher lymphocyte responses to both APV and ConA than birds vaccinated with inactivated APV/C. Conversely, animals that were not challenged with APV/C had higher lymphocyte responses to APV and ConA than vaccinated, APV/C-challenged groups. These results indicate vaccination with inactivated-APV/C does not increase cellular response to APV/C, and virus challenge may result in cellular immunosuppression.

Technical Abstract: Avian pneumovirus (APV) is the causative agent of turkey rhinotracheitis (TRT) which results in primarily a respiratory disease. Previous research in our lab indicates that inactivated APV vaccines do not induce serum virus-neutralizing antibodies and are not protective. The objective of this study was to compare cellular immune mechanisms of purified turkey lymphocytes from control and immunized birds . The effect of APV infection on the avian immune system was also examined by comparing APV-specific IgG and IgA antibodies following virus challenge.