Incorporation of a recombinant Eimeria maxima IMP1 antigen into nanoparticles confers protective immunity against E. maxima challenge infection

Authors: Jenkins, Mark; STEVENS, LAURA - Southern Illinois University; Obrien, Celia; Parker, Carolyn; Miska, Kate; KONJUFCA, VJOLLCA - Southern Illinois University

Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2017
Publication Date: 2/14/2018
Citation: Jenkins, M.C., Stevens, L., Obrien, C.N., Parker, C.C., Miska, K.B., Konjufca, V. 2018. Incorporation of a recombinant Eimeria maxima IMP1 antigen into nanoparticles confers protective immunity against E. maxima challenge infection. Vaccine. 36(8):1126-1131.

Interpretive Summary: Avian coccidiosis is an intestinal disease caused by a protozoan parasite named Eimeria. It causes over $ 350 million loss each year to the U.S. poultry industry, with worldwide losses exceeding $ 1.5 billion. At present, the disease is controlled by the medication of feed with anticoccidial drugs or the application of live low doses of Eimeria parasites to newly-hatched chicks. In addition to the greater demand for antibiotic-free poultry, there are problems with using anticoccidial drugs and vaccine including Eimeria drug-resistance and poor vaccination efficiency that leads to regular outbreaks of coccidiosis. In the present study, a subunit vaccine against Eimeria maxima, a particularly problematic strain of Eimeria, was produced by cloning an E. maxima gene into Escherichia coli, which then produced large amounts of the recombinant protein. This protein, named EmaxIMP1, was linked to nanoparticles and used to immunize chicks against coccidiosis. Our studies found that the nanoparticle-conjugated EmaxIMP1 migrated to various tissues in chickens and thereby elicited an immune response against E. maxima. Broiler chickens vaccinated with this formulation displayed partial to complete immunity against coccidiosis. These findings indicate that a subunit vaccine may be a useful alternative to drugs and live vaccines to control avian coccidiosis.

Technical Abstract: The purpose of this study was to determine if incorporating a recombinant Eimeria maxima protein, namely rEmaxIMP1, into gold nanoparticles (NP) could improve the level of protective immunity against E. maxima challenge infection. Recombinant EmaxIMP1 was expressed in Escherchia coli as a poly-His fusion protein, purified by NiNTA chromatography, and linked to 20 nm gold particles. Both rEMaxIMP1 or control non-recombinant (NR) protein were delivered per os to newly-hatched broiler chicks with subsequent booster immunizations at 3 and 21 days of age. In battery cage studies (n=4), chickens immunized with NP-rEMaxIMP1 displayed complete protection as measured by weight gain (WG) against E. maxima challenge compared to chickens immunized with NP-NR. WG in the NP-rEMaxIMP1-immunized groups was identical to WG in non-E. maxima infected chickens. In floor pen studies (n=2), chickens immunized with NP-rEMaxIMP1 displayed partial protection as measured by WG against E. maxima challenge compared to chickens immunized with NP-NR. In order to understand the basis for immune stimulation, newly-hatched chicks were inoculated with NP-rEMaxIMP1 or NP-NR protein; various tissues, including the small intestine, bursa, and spleen, were examined for NP localization at 1 and 6 h post-inoculation. Within 1 hr, both NP-rEMaxIMP1 and NP-NR were observed in all examined tissues, particularly in the small intestine. An increase was observed in the level of NP-rEmaxIMP1 and NP-NR in all tissues at 6 h post-inoculation. These data indicate that incorporating NP into rEmaxIMP1 and per os inoculation leads localization within 1-6 h to various tissues, and elicitation of complete to partial immunity against E. maxima challenge infection.