Acta Veterinaria et Zootechnica Sinica ›› 2023, Vol. 54 ›› Issue (10): 4338-4349.doi: 10.11843/j.issn.0366-6964.2023.10.030

• PREVENTIVE VETERINARY MEDICINE • Previous Articles     Next Articles

Evaluation of the Immunoprotective Effect of Recombinant Protein of Eimeria magna 3-Phosphoglyceraldehyde Dehydrogenase on Rabbits

ZHENG Ruoyu1, XIAO Jie1, BAI Xin1, CHEN Hao1, PU Jiayan1, REN Yongjun2,3*, YANG Guangyou1*   

  1. 1. College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China;
    2. Sichuan Animal Science Academy, Chengdu 610066, China;
    3. Animal Breeding and Genetics Key Laboratory of Sichuan Province, Chengdu 610066, China
  • Received:2023-01-30 Online:2023-10-23 Published:2023-10-26

Abstract: The aim of this study was to evaluate the immunoprotective effect of rEm-GAPDH, a recombinant protein of Eimeria magna, on rabbits and to lay the foundation for the development of a recombinant subunit immunization vaccine for rabbits. Screening of Em-GAPDH gene based on transcriptome data for prokaryotic expression and protein purification.Then 50 45-day-old coccidia-free rabbits were randomly divided into 5 groups (Unimmunized and unchallenged group, unimmunized and challenged group, Trx-His-S tag-challenged group, Quil-A saponin-challenged group and rEm-GAPDH immunized group). 1 mL PBS, 1 mL PBS, 1 mL PBS containing 100 μg pET-32a and 1 mg Quil-A, 1 mL PBS containing 1 mg Quil-A, 1 mL 100 μg rEm-GAPDH and 1 mg Quil-A were respectively injected subcutaneously via the neck to the rabbits, and were booster immunized with the same dose 14 d after the first immunization. The clinical manifestations of each group were observed after orally infected 1×105 sporulated oocysts of Eimeria magna to every rabbit, while blood sample and body weight data were collected at regular intervals every week. After 14 d of the challenge, rabbits were dissected, and oocyst output, relative weight gain, cytokines, and specific IgG antibodies were measured and counted for each group. The results showed that the recombinant protein rEm-GAPDH was successfully expressed, with a size of about 59 ku and mostly expressed in the inclusion bodies. The immunoprotection test showed that typical symptoms of rabbit intestinal coccidiosis appeared in the unimmunized and challenged group after infection, while rEm-GAPDH immunized group showed no significant symptoms. rEm-GAPDH immunized group showed 57.16% oocyst reduction, the relative weight gain rate was significantly greater than the unimmunized and challenged group (P<0.05), specific IgG antibody levels, cytokine (IFN-γ, IL-2, IL-4, IL-10, TGF-β) levels were significantly different from those of the control group (P<0.05). The ACI of rEm-GAPDH immunized group was 144.96. The recombinant protein rEm-GAPDH of E.magna can reduce weight loss and oocyst excretion, trigger cellular and humoral immune responses in the host, and have certain immunoprotective effects, thus can be used as a candidate antigen for E.magna recombinant subunit vaccine.

Key words: rabbit, Eimeria magna, 3-phosphoglyceraldehyde dehydrogenase, recombinant protein, immunoprotection

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