Evaluation of immune response elicited by the recombinant PmpD N terminal proteins of Chlamydia psittaci in SPF Chickens

• 1、The ministry of agriculture animal epidemiology and zoonoses key laboratory, Animal medical college of China agricultural university, Beijing 100193
• 2、Technology Promotion Center,Beijing Vica Group,Beijing 100085

Abstract：Polymorphic membrance proteins(Pmps) are located on the surface of Chlamydia psittaci and the potential functions are unclear so far. Moreover, PmpD N terminal is 64kD and belongs to the Pmp families.In order to evaluate PmpD N terminal, we cloned, expressed and purified the target protein. Subsequently, the recombinant protein vaccines were manufactured with the Frenz adjuvant.Furthermore, 21-day-old SPF chickens were administered with 100μg and 50μg of the recombinant proteins, respectively.After two weeks, the chickens were given the boosting immunization.The birds inoculated with 50μg of the recombinant MOMP were used as the positive group while the chickens with the adjuvant were regarded as the negative control. The blood samples were collected at days 7 post first immunization and the sera were also sampled at days 14 after second inoculation.The antibody levels against PmpD N terminal were detected by ELISA assay while the lymphocytes proliferation was determined by MTT approach.Finally, all birds were challenged intraperiteally with vivulant strain CB8 of C.psittaci and the pathogen excretions were detected using the commercial kits.Mean while, the lungs and spleens were collected and detected the chlamydial loads using the immunochemistry approach.Taken together, 100μg of the recombinant PmpD N proteins could induce a better humoral response and cellular response and no significant difference was found in comparison with the commercial vaccine, suggestion of the potential vaccine candidate against C.psittaci.

Keywords： Polymorphic membrance proteins PmpD N terminal immune response SPF chickens Chlamydophila psittaci