Characterization of Circulating Antibodies against Chlamydia psittaci in Turkeys

Plasma and joint fluids from turkeys experimentally inoculated with Chlamydia psittaci strain TT3 were evaluated by immunoblotting to identify antibodies elicited by chlamydial antigens during the course of infection. Protein antigens from elementary bodies of TT3 were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred electrophoretically to nitrocellulose before being probed with plasma or synovial fluid from TT3-inoculated birds. The major outer-membrane protein (MOMP), the 60,000-molecular-weight proteins, and a 97,400-molecular-weight protein were the predominant antigens recognized by IgG in the plasma and joint fluids. Plasma IgG specific for the 97,400 protein band was first detectable at day 10 postinoculation (PI). Antibodies to the 60,000-molecular-weight protein and MOMP were first detected at days 14-17 PI and at days 7-10 PI, respectively, in some birds, and as late as days 36-42 PI and days 42-70 PI in others. The antibodies were still present at day 142 PI. Immunoblotting techniques indicated that the antigens to which these antibodies were reacting were protein. These observations may have implications for the development of serodiagnostic assays as well as the identification of potential proteins for subunit immunogens in birds. /// El plasma y el líquido articular de pavos inoculados experimentalmente con la cepa TT3 de Chlamydia psittaci fueron evaluados por inmunotransferencia puntual para detectar anticuerpos estimulados por los antígenos de estas bacterias durante la infección. Los antígenos proteínicos de los corpúsculos elementales de la cepa TT3 fueron separados por electroforesis en un gel de poliacrilamida con dodecilsulfato de sodio y transferidos electroforéticamente a nitrocelulosa antes de ser tratados con el plasma o el líquido sinovial de las aves inoculadas con la cepa TT3. La proteína principal de la membrana externa, las proteínas de peso molecular (PM) 60,000 y una proteína de PM 97,400 fueron los antígenos predominantes reconocidos por la IgG en el plasma y el líquido articular. La IgG plasmática específica para la proteína de PM 97,400 fue detectable inicialmente a los 10 días postinoculación (PI). Los anticuerpos contra la proteína de PM 60,000 y la proteína principal de la membrana externa fueron detectados inicialmente a los 14-17 días PI y a los 7-10 días PI respectivamente en algunas de las aves y tan tardíamente como a los 36-42 días PI y 42-70 días PI en otras. Los anticuerpo