Journal Article

Induction of protective immunity against Eimeria tenella, Eimeria necatrix, Eimeria maxima and Eimeria acervulina infections using multivalent epitope DNA vaccines

Yan, Ruofeng, Xu, Lixin, Song, Xiaokai, Li, Xiangrui, Ren, Zhe

2015

Overview

•In this study, novel multivalent epitope DNA vaccines were constructed and they could provide effective protection against four Eimeria species.•The multivalent epitope DNA vaccines were basing on the comprehensive consideration of mixed infection and the critical role of cellular immunity in Eimeria infection.•The criterion of selection of T-cell epitope was the comprehensive consideration of epitope prediction and protective efficacy.•Our findings suggest that the multivalent epitope DNA vaccines are the potential candidate vaccines against mixed infection of Eimeria under natural conditions. Avian coccidiosis is mostly caused by mixed infection of several Eimeria species under natural conditions and immunity to avian coccidiosis is largely dependent on T-cell immune response. In this study, 14 T-cell epitope fragments from eight antigens of Eimeria tenella (E. tenella), Eimeria necatrix (E. necatrix), Eimeria maxima (E. maxima) and Eimeria acervulina (E. acervulina) were ligated with pVAX1 producing 14 monovalent DNA vaccines, respectively. Protective immunity of the monovalent DNA vaccines was assessed by in vivo challenge experiments and then four most protective fragments of each species were chosen to construct multivalent epitope DNA vaccines with or without chicken IL-2 as genetic adjuvant. Protective efficacies of the epitope DNA vaccines on chickens against E. tenella, E. necatrix, E. maxima and E. acervulina were evaluated. The results showed that the constructed multivalent epitope DNA vaccines significantly increased body weight gain, alleviated enteric lesions and reduced oocyst output of the infected birds. Especially, the multivalent epitope DNA vaccines of pVAX1-NA4-1-TA4-1-LDH-2-EMCDPK-1 and pVAX1-NA4-1-TA4-1-LDH-2-EMCDPK-1-IL-2 not only significantly increased body weight gain, alleviated enteric lesions and reduced oocyst output of the infected birds, but also resulted in anti-coccidial index (ACI) more than 170 against E. tenella, E. necatrix, E. maxima and E. acervulina, which indicated they could induce protective immunity against E. tenella, E. necatrix, E. maxima and E. acervulina. Our findings suggest the constructed multivalent epitope DNA vaccines are the potential candidate multivalent vaccines against mixed infection of Eimeria.

• Publisher: Elsevier Ltd,Elsevier Limited
• Subject: adjuvants / Adjuvants, Immunologic / Allergy and Immunology / Animals / Antigens / Antigens, Protozoan - immunology / Birds / Body weight / body weight changes / Chickens / Chickens - immunology / Cloning / coccidiosis / Coccidiosis - parasitology / Coccidiosis - prevention & control / coccidiostats / Cross-species protection / Deoxyribonucleic acid / DNA / DNA vaccine / Eimeria / Eimeria - immunology / Eimeria acervulina / Eimeria maxima / Eimeria necatrix / Eimeria tenella / Eimeria tenella - immunology / epitopes / Epitopes, T-Lymphocyte - immunology / Immune response / Infections / interleukin-2 / Interleukin-2 - genetics / Interleukin-2 - immunology / Isoenzymes - genetics / Isoenzymes - immunology / L-Lactate Dehydrogenase - genetics / L-Lactate Dehydrogenase - immunology / Lesions / mixed infection / Oocysts / Parasites / Pets / Plasmids / Poultry / Poultry Diseases - prevention & control / Protozoan Vaccines - immunology / recombinant vaccines / T-cell epitope / T-lymphocytes / Vaccines / Vaccines, DNA - administration & dosage / Vaccines, DNA - immunology