马流感病毒血凝素基因甲病毒复制子重组表达质粒的构建及其免疫效力评价

Immunization responses against equine influenza virus(EIV) based on recombinant Alphavirus replicon plasmid expressing EIV hemagglutinin gene

为评价马流感病毒(EIV)HA基因核酸免疫效果,本研究以甲病毒复制子载体pSFV1CS分别构建了表达EIV H3N8亚型的美洲型和欧洲型HA基因的重组真核表达质粒。并将其转染293T细胞,经间接免疫荧光鉴定表明HA基因获得表达;以重组质粒免疫的BALB/c鼠能够检测到特异性抗体产生,而且HI抗体水平持续升高,同时小鼠体内IFN-γ、IL-4分泌水平也有所升高。攻毒后小鼠表现轻度临床症状,但病毒分离和RT-PCR均未检测到病毒。上述结果表明,该重组质粒pSFV1CS-EIV-HA具有良好的免疫原性并且可以诱导免疫动物产生较高免疫应答的能力。

To evaluate DNA vaccination against equine influenza virus （EIV）, the hemagglutinin （HA） genes of American and European H3N8 subtype EIV were amplified by RT-PCR and cloned into a Semliki forest virus （SFV） replicon based plasmid of pSFV to construct the recombinant plasmid pSFV1CS-EIV-HA, respectively. The HA expressions were identified in the 293T cells transfected with the recombinant plasmid by indirect immunofluorescence assay. Furthermore, the specific HI antibody, IFN-γ or IL-4 level were detected in BALB/c mice immunized with either single or both of the recombinant plasmids. However, the virus was failed to detect in immunized BALB/c mice by the RT-PCR detection or the virus isolation. The results indicated that the recombinant plasmids possessed a capability for inducing effective immune responses in animals, which was a promising candidate DNA vaccine against EIV infection.