Tran Ha Thi Thanh, Truong Duc Anh, Ly Viet Duc, Vu Hao Thi, Hoang Tuan Van, Nguyen Chinh Thi, Chu Nhu Thi, Nguyen Vinh The, Nguyen Duyen Thuy, Miyazawa Kohtaro, Kokuho Takehiro, Dang Hoang Vu
Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam.
National Institute of Animal Health, The National Agriculture and Food Research Organization, Tsukuba, Japan.
Clin Exp Vaccine Res. 2020 Jan;9(1):26-39. doi: 10.7774/cevr.2020.9.1.26. Epub 2020 Jan 31.
To date, many kinds of classical swine fever (CSF) vaccines have been developed to protect against this disease. However, the efficacy of these vaccines to protect the pig against field CSF strains needs to be considered, based on circulating strains of classical swine fever virus (CSFV).
Recombinant E2-CSFV protein produced by baculovirus/insect cell system was analyzed by western blots and immunoperoxidase monolayer assay. The effect of CSFV-E2 subunit vaccines was evaluated in experimental pigs with three genotypes of CSFV challenge. Anti-E2 specific and neutralizing antibodies in experimental pigs were analyzed by blocking enzyme-linked immunosorbent assay and neutralization peroxidize-linked assay.
The data showed that CSFV VN91-E2 subunit vaccine provided clinical protection in pigs against three different genotypes of CSFV without noticeable clinical signs, symptoms, and mortality. In addition, no CSFV was isolated from the spleen of the vaccinated pigs. However, the unvaccinated pigs exhibited high clinical scores and the successful virus isolation from spleen. These results showed that the E2-specific and neutralizing antibodies induced by VN91-E2 antigen appeared at day 24 after first boost and a significant increase was observed at day 28 (p<0.01). This response reached a peak at day 35 and continued until day 63 when compared to controls. Importantly, VN91-E2 induced E2-specific and neutralizing antibodies protected experimental pigs against high virulence of CSFVs circulating in Vietnam, including genotype 1.1, 2.1, and 2.2.
These findings also suggested that CSFV VN91-E2 subunit vaccine could be a promising vaccine candidate for the control and prevention of CSFV in Vietnam.
迄今为止，已研发出多种经典猪瘟（CSF）疫苗来预防这种疾病。然而，基于经典猪瘟病毒（CSFV）的流行毒株，需要考虑这些疫苗对猪抵御田间CSF毒株的有效性。
通过蛋白质免疫印迹法和免疫过氧化物酶单层试验分析杆状病毒/昆虫细胞系统产生的重组E2-CSFV蛋白。用三种基因型的CSFV攻击实验猪，评估CSFV-E2亚单位疫苗的效果。通过阻断酶联免疫吸附试验和中和过氧化物酶联试验分析实验猪体内的抗E2特异性抗体和中和抗体。
数据显示，CSFV VN91-E2亚单位疫苗为猪提供了针对三种不同基因型CSFV的临床保护，未出现明显的临床症状、体征和死亡情况。此外，未从接种疫苗猪的脾脏中分离出CSFV。然而，未接种疫苗的猪表现出高临床评分，且从脾脏中成功分离出病毒。这些结果表明，VN91-E2抗原诱导的E2特异性抗体和中和抗体在首次加强免疫后第24天出现，第28天观察到显著增加（p<0.01）。与对照组相比，这种反应在第35天达到峰值，并持续到第63天。重要的是，VN91-E2诱导的E2特异性抗体和中和抗体保护实验猪免受在越南流行的高毒力CSFVs的侵害，包括1.1、2.1和2.2基因型。
这些发现还表明，CSFV VN91-E2亚单位疫苗可能是越南控制和预防CSFV的一种有前景的候选疫苗。
