Vaccines and Immunization

Biography

Biography: Cheng He

Abstract

Avian Chlamydia psittaci (C. psittaci) is threating to poultry industry as well as the closely contacted humans due to highly prevalence and lack of the commercial vaccine. A novel nanoparticle vaccine with the cellular-elicited adjuvant was prepared to achieve a better immune response against C. psittaci infection and it included a gel-formed or a microsphere-formed chitosan as a deliver particle, standard CPG or VCG as the adjuvant and the inactivated elemental bodies of C. psittaci. Total of 105 SPF chickens aged 7-day old was divided into seven groups, 15 birds per group. Chickens received the nanovaccine with CpG or VCG adjuvant by intranasal administration or by intramuscular route. Meanwhile, birds were inoculated with r-MOMP, or inactivated whole EB or gel chitosan or microsphere chitosan as the control group. All above groups were immunized and boosted with 14 day interval. Post immunization, C. psittaci specific antibodies were detected weekly. After boosting, lymphocyte proliferation, T cell subsets, cytokines were monitored using commercial kits. Finally, birds were challenged with 1×108 IFU/ml live EBs of virulent C. psittaci via larynx inoculation and chlamydial shedding were determined using cell culture. Post prime-boost strategy, birds with VCG-adjuvant nanoparticle induced an increasing-trend antibody and no statistical difference was found as compared to rMOMP vaccine. However, VCG-adjuvant nanoparticle yielded a highly splenic lymphocyte proliferation, CD4+/CD8+ ratio, as well as significant elevation of IFN-γ, IL-2 and IL12p40 in lung lavage fluids. Moreover, a reducing trend of chlamydial shedding was found in the birds with VCG-adjuvant nanoparticle. Lesion index in lungs and air sacs were also reduced in the birds with the VCG-adjuvant nanoparticle vaccine. Taken together, VCG-adjuvant nanoparticle vaccine via mucosal immunization is a promising approach against C. psittaci infection.