Principal Investigator: Li Xiangrui

Funding Received: 2.5 Million RMB

Sponsored by: National Natural Science Foundation of China (NSFC)

Project Period: August, 2016-July, 2019

Brief Introduction to the Project:

  Avian coccidiosis is one of the diseases that cause significant economic losses to the poultry industry. Chemotherapy has been the dominant method to control coccidiosis; however, the application of anti-coccidial drugs has been limited due to the generation of drug-resistant strains of Eimeria and the problem of drug residue, and the disadvantages of easy prevalence, high cost and difficulty in saving have restricted the application of traditional live oocyst vaccine. A neo-type vaccine, DNA or a subunit vaccine, with the advantages of security, simplicity in producing and applying, has drawn increasing attention of researchers all over the world. Dendritic cells (DCs) are professional antigen sensing cells and highly efficient antigen presenting cells that link innate and adaptive immunity. It has been demonstrated that Eimeria infection could activate DCs and that the Eimeria antigen could bind with DCs, and the Ag-binding DCs could then trigger the cellular and humoral immune response efficiently. However, the specific DCs-stimulating antigen is still not clear. In this study, we will firstly clarify the specific DCs-stimulating antigens. Chickens will be orally infected with E. tenella, E. necatrix, E. acervulina, and E. maxima. Then, the caecal tonsil and Peyer’s patches of the infected chickens will be collected to isolate the gut DC which will be identified by morphologic and phenotypic analysis. After that, the DCs-stimulating antigen proteins will be identified using the co-immunoprecipitation assay. The DCs stimulating ability of the DCs-stimulating antigen will be confirmed in vivo and in vitro. The antigen with robust ability of stimulating DCs will be selected as subunit vaccines, and their genes will be cloned into eucaryotic expression plasmids to construct DNA vaccine. At the same time, the subunit vaccine and DNA vaccines will be coated with the nanomaterial PLGA (poly(D,L-lactic-co-glycolic acid)) to construct nano-subunit vaccines and nano-DNA vaccines. Subsequently, chickens will be vaccinated with the naked DNA vaccine, nano-DNA vaccine, subunit vaccine and nano-subunit vaccine to detect the induced cellular and humoral responses. Finally, animal experiments will be carried out to determine the protective efficacy of the naked DNA vaccine, nano-DNA vaccine, subunit vaccine and nano-subunit vaccine against chicken coccidiosis. The present research would provide effective candidate antigens for developing nano-vaccines and reference for controlling chicken coccidiosis.