Plant expressed coccidial antigens as potential vaccine candidates in protecting chicken against coccidiosis.

Coccidiosis is a disease caused by intracellular parasites belonging to the genus Eimeria. In the present study, we transiently expressed two coccidial antigens EtMIC1 and EtMIC2 as poly histidine-tagged fusion proteins in tobacco. We have evaluated the protective efficacy of plant expressed EtMIC1 as monovalent and as well as bi-valent formulation where EtMIC1 and EtMIC2 were used in combination. The protective efficacy of these formulations was evaluated using homologous challenge in chickens. We observed better serum antibody response, weight gain and reduced oocyst shedding in birds immunized with EtMIC1 and EtMIC2 as bivalent formulation compared to monovalent formulation. However, IFN-γ response was not significant in birds immunized with EtMIC1 compared to the birds immunized with EtMIC2. Our results indicate the potential use of these antigens as vaccine candidates.

Plant expressed EtMIC2 is an effective immunogen in conferring protection against chicken coccidiosis.

Coccidiosis is an economically important disease affecting poultry industry and remains one of the major problems globally. Developing a cost effective sub-unit vaccine may help mitigate loss in the industry. Here, we report expressing one of the microneme proteins, EtMIC2 from Eimeria tenella in tobacco using Agrobacterium-mediated transient expression. The ability of plant expressed recombinant EtMIC2 in eliciting both humoral and cell-mediated immune responses were measured in the immunized birds. The protective efficacy in the vaccinated birds against a homologous challenge was also evaluated. Birds immunized with plant expressed EtMIC2 showed good sero-conversion, reduced oocyst output and increased weight gain when compared to control birds. Our data indicate that use of plant expressed recombinant EtMIC2 in birds was safe and had the potential in imparting partial protection in chickens against homologous challenge.

Cloning, expression and evaluation of the efficacy of a recombinant Eimeria tenella sporozoite antigen in birds.

Eimeria infection in poultry is of significant economic interest worldwide. Development of a cost-effective sub-unit vaccine that provides cross-protection may help reduce loss in poultry industry. One approach explored by many investigators is to block the parasite invasion into gut epithelium. Use of microneme proteins to prevent parasite invasion is one of the most straightforward approaches in developing a preventive vaccine. Here we describe cloning and expression of microneme-1 protein of Eimeria tenella, obtained from an outbreak sample from India. We have evaluated the ability of the recombinant protein to elicit both cell mediated immune (CMI) and humoral immune responses. We also evaluated the efficacy of the recombinant protein in protecting against a homologous challenge. Our data indicate recombinant EtMIC1 is able to impart partial protection against homologous challenge in chicken. Inclusion of more invasion proteins may improve the efficacy of prophylactic vaccine against Coccidiosis.