Acta Veterinaria et Zootechnica Sinica ›› 2025, Vol. 56 ›› Issue (10): 5072-5083.doi: 10.11843/j.issn.0366-6964.2025.10.027

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Prokaryotic Expression of Porcine Soluble CD40L Trimer Protein and Evaluation of Its Immune Effect against Foot-and-Mouth Disease Virus-Like Particles Vaccine

HE Yanyan1,2(), CHEN Lingbo1, WEI Tian1, TENG Zhidong1, ZHANG Yun1, ZHANG Mingyang1, MA Wenqian1, JING Xiaoqi2, GUO Huichen1, MU Suyu1,*(), SUN Shiqi1,*()   

  1. 1. National Key Laboratory of Animal Disease Prevention and Control, School of Animal Medicine and Biosafety, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou University, Lanzhou 730030, China
    2. College of Advanced Agricultural Sciences, Yulin University, Yulin 719000, China
  • Received:2025-01-10 Online:2025-10-23 Published:2025-11-01
  • Contact: MU Suyu, SUN Shiqi E-mail:160631841@qq.com;mutou6633937@126.com;sunshiqi@caas.cn

Abstract:

This study aimed to evaluate the immune-enhancing effect of porcine soluble CD40L trimer protein on the Virus-like particles (VLPs) vaccine of Foot-and-mouth disease (FMD). In this study, the plasmid containing porcine CD40 ligand (CD40L) trimer (5B CD40L) gene was expressed in Escherichia coli BL21(DE3). The purified recombinant 5B CD40L protein was coupled to FITC and reacted with PBMCs. The biological activity of CD40L protein reacting with monocytes was studied by fluorescence microscopy. The guinea pigs were further immunized with 5B CD40L, VLPs and 5B CD40L-VLPs, and the effects of 5B CD40L on the immune effect of VLPs vaccine were evaluated by neutralizing antibodies, splenic lymphocyte proliferation and real-time RT-qPCR. SDS-PAGE and Western blot results showed that the size of recombinant 5B CD40L protein expressed was about 32 ku. The optimal expression conditions were 16℃, OD600 nm value was 0.9, and concentration was 0.5 mmol L-1 after IPTG induction for 12 h. Flow cytometry analysis showed that the recombinant CD40L protein could bind to CD40 protein molecules on the surface of porcine peripheral blood mononuclear cells (PBMCs). The combination of 5B CD40L and VLPs can accelerate the reaction of specific antibody and neutralizing antibody, and improve the proliferation level of spleen lymphocytes. In the 5B CD40L-VLPs group, the IL-2 and INF-γ mRNA of spleen cells are significantly higher than those in the VLPs group. In summary, 5B CD40L has the ability to enhance humoral and cellular immune responses of FMD VLPs vaccine, and has the potential as a vaccine adjuvant.

Key words: 5B CD40L, Foot-and-mouth disease, immune effect

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