短肽佐剂对猪繁殖与呼吸综合征病毒弱毒疫苗CH-1R株的免疫增强作用研究

Enhancement of the immune efficacy on porcine reproductive and respiratory syndrome CH-1R vaccine by oligopeptide adjuvant

为评价一种短肽佐剂对猪繁殖与呼吸综合征病毒(PRRSV)CH-1R弱毒疫苗的免疫增强效果,本研究分别采用CH-1R疫苗株单独(单独免疫组)、CH-1R疫苗株与短肽佐剂共同(共同免疫组)及生理盐水(对照组)免疫仔猪,4周后以高致病性PRRSV(H P-PRRSV)TJ-F5攻毒,并采用流式细胞术对攻毒前后淋巴细胞亚类T、Th、Tc及N K进行绝对和相对计数。结果显示攻毒后共同免疫组仅在第3 d淋巴细胞亚类数量显著下降后回升,28 dTc/T显著高于单独免疫组,临床症状和各组织器官病理变化轻微;单独免疫组在攻毒后第3 d淋巴细胞亚类数量显著下降后回升,之后于第14和15 d再次显著下降后又回升,临床症状和各组织器官病理变化比共同免疫组严重,但比对照组明显减轻。单独免疫组、共同免疫组及对照组的攻毒保护率分别为40%、80%、0。研究结果表明,短肽佐剂配合CH-1R弱毒疫苗具有缓解H P-PRRSV TJ-F5的免疫抑制、增强细胞免疫及提高免疫保护力的作用;在抵抗H P-PRRSV TJ-F5攻击时,共同免疫组的免疫保护力明显高于单独免疫组。

To evaluate the immune enhancement of a oligopeptide adjuvant to the porcine reproductive and respiratory syndrome virus （PRRSV） attenuated vaccine, piglets were inoculated with PRRSV CH-1R vaccine strain diluted with saline （single vaccine group）, PRRSV CH-1R vaccine strain diluted with the oligopeptide adjuvant （co-vaccination group） and saline only （control group）, respectively, and challenged with highly pathogenic PRRSV （HP-PRRSV） TJ-F5 strain on 28 day post vaccination. In addition, the change of lymphocyte subpopulations and NK cells were analyzed by flow cytometrer. The results showed that the subpopulations of T, Th, Tc and NK cells reduced significantly only at 3 days post challenge （dpc） in co-vaccination group and then increased, moreover, the ratio of Tc/T cells was significantly higher than that in single vaccine group at 28 dpc. However, the T, Th, Tc and NK cells reduced significantly in single vaccine group at 3 dpc and then increased, but reduced significantly at 14 and 15 dpc and then increased again. The clinical symptom and tissues lesions were more serious than in co-vaccination group, but less mild than in control group. The protections of single vaccine group, co-vaccination group and control group were 40%, 80% and 0, respectively. These findings indicated that the oligopeptide adjuvant was able to alleviate the immunosuppression post challenge, enhance the cellular immune response and improve protective efficacy of PRRSV CH-1R attenuated vaccine against HP-PRRSV.