Protective immunity against Eimeria maxima induced by vaccines of Em14-3-3 antigen

Area of Science:

• Veterinary Parasitology
• Molecular Biology
• Immunology

Background:

• Eimeria maxima is a significant poultry pathogen causing coccidiosis.
• Effective vaccines are crucial for controlling E. maxima infections in poultry farming.

Purpose of the Study:

• To investigate the potential of Eimeria maxima 14-3-3 (Em14-3-3) as a vaccine candidate against E. maxima.
• To evaluate the immunogenicity and efficacy of Em14-3-3 in chickens.

Main Methods:

• Amplification, sequencing, and subcloning of the Em14-3-3 open reading frame (ORF).
• In vivo expression analysis using RT-PCR and immunoblotting.
• Immunofluorescence to determine Em14-3-3 localization.
• Animal experiments to assess protection against E. maxima challenge, including lesion scoring, weight gain, oocyst shedding, and immune response analysis (CD4+ T cells, antibody titers, cytokine levels).

Main Results:

• Em14-3-3 was successfully cloned, transcribed, and expressed in vivo, localized in sporozoites and merozoites.
• Vaccination with rEm14-3-3 and pVAX1-14-3-3 significantly alleviated jejunum lesions and body weight loss.
• Vaccinated groups showed increased oocyst reduction ratios and anticoccidial indices (>165).
• Higher percentages of CD4+ T cells, elevated anti-Em14-3-3 antibody titers, and increased IFN-γ and TGF-β levels were observed in immunized groups compared to controls.

Conclusions:

• Em14-3-3 is expressed during E. maxima infection and elicits protective immune responses.
• Em14-3-3 serves as a promising antigen candidate for developing effective vaccines against E. maxima.