Zhang Yudi, Zhang Xiaohui, Liao Xiaodan, Huang Xiaobo, Cao Sanjie, Wen Xintian, Wen Yiping, Wu Rui, Liu Wumei
Research Center of Swine Disease and Laboratory of Animal Infectious Disease and Microarray, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China.
Virus Genes. 2016 Jun;52(3):354-64. doi: 10.1007/s11262-016-1316-z. Epub 2016 Mar 15.
Porcine transmissible gastroenteritis virus (TGEV) and porcine epidemic diarrhea virus (PEDV) can cause severe diarrhea in newborn piglets and led to significant economic losses. The S proteins are the main structural proteins of PEDV and TGEV capable of inducing neutralizing antibodies in vivo. In this study, a DNA vaccine SL7207 (pVAXD-PS1-TS) co-expressing S proteins of TGEV and PEDV delivered by attenuated Salmonella typhimurium was constructed and its immunogenicity in piglets was investigated. Twenty-day-old piglets were orally immunized with SL7207 (pVAXD-PS1-TS) at a dosage of 1.6 × 10(11) CFU per piglet and then booster immunized with 2.0 × 10(11) CFU after 2 weeks. Humoral immune responses, as reflected by virus neutralizing antibodies and specific IgG and sIgA, and cellular immune responses, as reflected by IFN-γ, IL-4, and lymphocyte proliferation, were evaluated. SL7207 (pVAXD-PS1-TS) simultaneously elicited immune responses against TGEV and PEDV after oral immunization. The immune levels started to increase at 2 weeks after immunization and increased to levels statistically significantly different than controls at 4 weeks post-immunization, peaking at 6 weeks and declined at 8 weeks. The humoral, mucosal, and cellular immune responses induced by SL7207 (pAXD-PS1-TS) were significantly higher than those of the PBS and SL7207 (pVAXD) (p < 0.01). In particular, the levels of IFN-γ and IL-4 were higher than those induced by the single-gene vaccine SL7207 (pVAXD-PS1) (p < 0.05). These results demonstrated that SL7207 (pVAXD-PS1-TS) possess the immunological functions of the two S proteins of TGEV and PEDV, indicating that SL7207 (pVAXD-PS1-TS) is a candidate oral vaccine for TGE and PED.
猪传染性胃肠炎病毒（TGEV）和猪流行性腹泻病毒（PEDV）可导致新生仔猪严重腹泻，并造成重大经济损失。S蛋白是PEDV和TGEV的主要结构蛋白，能够在体内诱导中和抗体。在本研究中，构建了一种由减毒鼠伤寒沙门氏菌递送的共表达TGEV和PEDV S蛋白的DNA疫苗SL7207（pVAXD - PS1 - TS），并研究了其在仔猪中的免疫原性。20日龄仔猪以每头仔猪1.6×10¹¹CFU的剂量口服免疫SL7207（pVAXD - PS1 - TS），2周后以2.0×10¹¹CFU进行加强免疫。评估了由病毒中和抗体、特异性IgG和sIgA反映的体液免疫反应，以及由IFN -γ、IL - 4和淋巴细胞增殖反映的细胞免疫反应。口服免疫后，SL7207（pVAXD - PS1 - TS）同时引发了针对TGEV和PEDV的免疫反应。免疫水平在免疫后2周开始升高，在免疫后4周升高到与对照组有统计学显著差异的水平，在6周达到峰值，在8周下降。SL7207（pAXD - PS1 - TS）诱导的体液、黏膜和细胞免疫反应显著高于PBS和SL7207（pVAXD）组（p < 0.01）。特别是，IFN -γ和IL - 4的水平高于单基因疫苗SL7207（pVAXD - PS1）诱导的水平（p < 0.05）。这些结果表明，SL7207（pVAXD - PS1 - TS）具有TGEV和PEDV两种S蛋白的免疫功能，表明SL7207（pVAXD - PS1 - TS）是TGE和PED的候选口服疫苗。
