Harnessing bioinformatics and recombinant technology to combat avian coccidiosis: A 19-kDa sporozoite protein-based vaccine.

Abstract

BACKGROUND: Coccidiosis is an economically important disease caused byspecies in poultry. AIM: This study aimed to design, express, and evaluate a recombinant 19-kDa sporozoite protein (E19kDa) as a vaccine candidate against mixedinfection in broiler chickens. METHODS: The study used bioinformatic analysis, protein expression analysis, immunization trials, and immune response evaluation were performed. Protein properties were predicted using bioinformatics tools. Gene 838 (Accession No. PV347147) was cloned into a pET-28b plasmid and expressed inBL21(DE3). IPTG induction levels were optimized, and expression was confirmed via quantitative PCR. The protein was purified using Ni-NTA chromatography and validated by SDS-PAGE. Twenty Ross 308 chickens were divided into negative control, positive control (infected), and challenge group. Birds in the vaccine group received two subcutaneous doses of E19kDa with aluminum hydroxide adjuvant. The challenge was performed using a mixedoocyst suspension (1 × 10⁴ oocysts per species). Immunity was assessed through live weight, oocyst counts, white blood cell counts, and IgY levels. RESULTS: The results showed high expression of E19kDa at 1 mM IPTG. SDS-PAGE confirmed the purified protein at ~29kDa. Immunized birds exhibited better weight gain, lower oocyst counts (10,245 versus 22,755), and increased white blood cell counts and IgY titers compared with infected controls. Enzyme-linked immunosorbent assay confirmed a peak antibody response on day 28 post-vaccination. The vaccine significantly reduced clinical symptoms and mortality. CONCLUSION: This study highlights the potential of the recombinant E19kDa protein as a promising candidate vaccine against coccidiosis. The approach combining bioinformatics, molecular expression, and immunological testing offers a cost-effective solution for the disease.