Transgenic Eimeria tenella Expressing Profilin of Eimeria maxima Elicits Enhanced Protective Immunity and Alters Gut Microbiome of Chickens

Abstract

Coccidiosis is one of the most serious diseases of livestock and birds in the world. Vaccination with live-parasite anticoccidial vaccines with genetic manipulation improving the immunogenicity of vaccine strains would be the best means for controlling coccidiosis in breeder and layer stocks, even in fast-growing broilers. Profilin from apicomplexan parasites is the first molecularly defined ligand for Toll-like receptor 11 (TLR11) and TLR12 in mice and is a potential molecular adjuvant. Here, we constructed a transgenic line (Et-EmPro) expressing the profilin of, the most immunogenic species of chicken coccidia, and evaluated the adjuvant effects of EmPro on the immunogenicity of We found that immunization with the transgenic parasites, compared with the wild type, elicited greater parasite antigen-specific cell-mediated immunity, characterized by increased numbers of interferon gamma (IFN-γ)-secreting lymphocytes. The transgenic parasite also induced better protective immunity against challenge than the wild type. In addition, the diversity of the fecal microbiome of the birds immunized with the transgenic parasite differed from that of the microbiome of the wild-type-immunized birds, indicating interactions of with the gut microbiome of chickens. Our results showing enhanced immunogenicity of by use of EmPro as a molecular adjuvant derived from the most immunogenic affinis species represent a large step forward in the development of the next generation of coccidiosis vaccines using as a vaccine platform expressing molecular adjuvants and potentially other pathogen antigens against not only coccidiosis but also other infectious diseases.

Co-immunization with two recombinant Eimeria tenella lines expressing immunoprotective antigens of E. maxima elicits enhanced protection against E. maxima infection

“…The expression cassette was controlled by the EtSAG13 ( E. tenella surface antigen 13) promoter (Fig. 1a) [25]. Eimeria tenella sporozoites were transfected with the linearized pSDEP2AAMA1S plasmid and then inoculated into the cloacal opening of chicks.…”

“…Solutions include but are not limited to: (i) using advanced biotechnological tools to discover new immunodominant antigen(s) of Eimeria , such as IMP1 [26]; (ii) improving the heterologous antigen expression level by using a stronger promoter or increasing the gene copy number, etc. [24]; (iii) co-expressing multiple immunodominant antigens mediated by P2A in one recombinant Eimeria line or by double or multiple expression cassette [24, 39]; (iv) optimizing the antigens’ location in recombinant Eimeria for efficient recognition by host immune system [18]; and (v) fusion expression of heterologous antigens with cytokine(s) or other molecular adjuvants [21, 25, 40].…”

Genetic modification of the protozoan Eimeria tenella using the CRISPR/Cas9 system

“…With its distinct biology and immunology, the Eimeria parasite also holds promise as a model organism for protozoan research. The establishment of transient transfection and stable selection protocols has greatly enhanced dissection of several biological and immunological properties in this parasite [2,3]. Nevertheless, the absence of an effective gene editing system has left many questions about functions of Eimeria's unique genes unanswered.…”

Towards Innovative Design and Application of Recombinant Eimeria as a Vaccine Vector

“…Recombinant Eimeria-expressing immunoglobulin Fc fragment with surface display that is fused with the glycosylphosphatidylinositol (GPI) anchor at its C terminus also enhances the protection of chickens against wild-type Eimeria infection (53). It was found that antigen derived from immunogenic species of Eimeria can serve as an adjuvant enhancing the immunogenicity of other Eimeria species, i.e., recombinant E. tenella expressing E. maxima profilin increases the immunogenicity of E. tenella, which elicits stronger cell-mediated immunity and provides better protection against E. tenella infection (54). All these findings indicate that it is feasible to genetically modify Eimeria for use as a novel vaccine vector and a safe and efficient coccidiosis vaccine.…”