Fathi Najafi M, Rahman Mashhadi M, Hemmaty M
Mashhad Branch, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran.
Department of Clinical Pathology, Faculty of Veterinary, University of Tehran, Tehran, Iran.
Arch Razi Inst. 2020 Oct;75(3):385-395. doi: 10.22092/ari.2019.121825.1267. Epub 2020 Oct 1.
Toxoid vaccines can provide protective immunity against clostridial diseases. Since the duration of the toxoid vaccine immunogenicity is short, these vaccines need to contain an adjuvant. The nanoparticles of chitosan can stimulate humoral and cell-mediated immune responses. In the present study, the effect of chitosan nanoparticles was investigated on the immunogenicity of the pentavalent clostridial toxoid vaccine containing Clostridium perfringens types D, C, and B, Clostridium septicum, as well as Clostridium novyi. Rabbits were immunized by two injections with 3-week intervals and checked clinically and through autopsy 2 weeks after the last injection. Hematological changes were investigated during immunization, including the changes of white and red blood cell counts, hemoglobin, packed cell volume, platelet, neutrophil, lymphocyte, eosinophil, basophile, monocyte, and Neut/Lymph. Biochemical factors, namely creatinine, blood urea nitrogen, glucose, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total protein, and albumin, were also studied. The changes in immune responses during the immunization period were investigated through indirect enzyme-linked immunosorbent assay (ELISA). The results of ELISA showed that chitosan significantly enhanced immunogenicity when accompanied with in the pentavalent clostridial toxoid vaccine. During the immunogenicity period and following that, no changes were observed in clinical behavior and internal organs after autopsy. The hematological and biochemical factors were reported with no significant pathologic changes during immunization in the control and vaccinated groups (p <0.05). The obtained findings revealed that the toxoid vaccines could not induce significant physiological changes in the body. The vaccine containing chitosan could stimulate humoral immunity 2-3 times higher than the nonchitosan vaccine. The humoral immune response was significantly duplicated due to the chitosan effect. Chitosan not only had no local or general side effects but also could be a good help with the enhancement of the immune system; therefore, it can be recommended as an appropriate safe adjuvant in the development of toxoid vaccines.
类毒素疫苗可提供针对梭菌性疾病的保护性免疫。由于类毒素疫苗免疫原性的持续时间较短，这些疫苗需要含有佐剂。壳聚糖纳米颗粒可刺激体液免疫和细胞介导的免疫反应。在本研究中，研究了壳聚糖纳米颗粒对含有D型、C型和B型产气荚膜梭菌、败血梭菌以及诺维氏梭菌的五价梭菌类毒素疫苗免疫原性的影响。兔子每隔3周进行两次注射免疫，并在最后一次注射后2周进行临床检查和尸检。在免疫过程中研究血液学变化，包括白细胞和红细胞计数、血红蛋白、血细胞比容、血小板、中性粒细胞、淋巴细胞、嗜酸性粒细胞、嗜碱性粒细胞、单核细胞以及中性粒细胞/淋巴细胞的变化。还研究了生化指标，即肌酐、血尿素氮、葡萄糖、丙氨酸转氨酶、天冬氨酸转氨酶、碱性磷酸酶、总蛋白和白蛋白。通过间接酶联免疫吸附测定（ELISA）研究免疫期间免疫反应的变化。ELISA结果表明，壳聚糖与五价梭菌类毒素疫苗一起使用时可显著增强免疫原性。在免疫原性期间及之后，尸检后临床行为和内部器官未观察到变化。对照组和接种疫苗组在免疫期间血液学和生化指标均未报告有明显病理变化（p＜0.05）。所得结果表明，类毒素疫苗不会在体内引起明显的生理变化。含壳聚糖的疫苗可刺激体液免疫，比不含壳聚糖的疫苗高2至3倍。由于壳聚糖的作用，体液免疫反应显著增强。壳聚糖不仅没有局部或全身副作用，而且对增强免疫系统有很大帮助；因此，在类毒素疫苗的研发中，它可作为一种合适的安全佐剂被推荐使用。
