背景:鸡球虫病是一种原生动物疾病,在家禽业中导致相当大的经济损失。活卵囊疫苗接种是目前预防球虫病的最有效措施。然而,它提供了有限的保护,有几个缺点,如免疫保护差和潜在的毒力逆转。因此,仍然迫切需要开发针对鸡球虫病的有效和安全的疫苗。
方法:在本研究中,通过构建表达E.tenellaRON2蛋白的重组植物乳杆菌(NC8)菌株,开发了一种新型的抗Eimeriatenella的口服疫苗。我们在3、4和5日龄和17、18和19日龄分别口服给予重组植物乳杆菌。同时,商业疫苗组中的每只小鸡用3×102个球虫活卵囊免疫。在30天时在每只鸡中接种总共5×104个E.tenella孢子形成的卵囊。然后,在E.tenella感染后评估免疫保护效果。
结果:结果显示,CD4+和CD8+T细胞的比例,脾淋巴细胞的增殖能力,重组植物乳杆菌免疫雏鸡的炎性细胞因子水平和特异性抗体滴度显著升高(P<0.05)。E.tenella攻击后,相对体重增加增加,每克卵囊(OPG)数量减少。此外,病变评分和盲肠组织病理学切片显示,重组植物乳杆菌可明显减轻盲肠的病理损伤。重组植物乳杆菌组的ACI为170.89,高于商业疫苗组的150.14。
结论:上述结果表明,表达RON2的植物乳杆菌改善了体液和细胞免疫,并增强了对E.tenella的免疫保护。保护效力优于用商业活卵囊疫苗接种的保护效力。这项研究表明,表达RON2蛋白的重组植物乳杆菌为针对球虫病的疫苗开发提供了有希望的策略。
BACKGROUND: Chicken coccidiosis is a protozoan disease that leads to considerable economic losses in the poultry industry. Live oocyst vaccination is currently the most effective measure for the prevention of coccidiosis. However, it provides limited protection with several drawbacks, such as poor immunological protection and potential reversion to virulence. Therefore, the development of effective and safe vaccines against chicken coccidiosis is still urgently needed.
METHODS: In this study, a novel oral
vaccine against Eimeria tenella was developed by constructing a recombinant Lactobacillus plantarum (NC8) strain expressing the E. tenella RON2 protein. We administered recombinant L. plantarum orally at 3, 4 and 5 days of age and again at 17, 18 and 19 days of age. Meanwhile, each chick in the commercial
vaccine group was immunized with 3 × 102 live oocysts of coccidia. A total of 5 × 104 sporulated oocysts of E. tenella were inoculated in each chicken at 30 days. Then, the immunoprotection effect was evaluated after E. tenella infection.
RESULTS: The results showed that the proportion of CD4+ and CD8+ T cells, the proliferative ability of spleen lymphocytes, inflammatory cytokine levels and specific antibody titers of chicks immunized with recombinant L. plantarum were significantly increased (P < 0.05). The relative body weight gains were increased and the number of oocysts per gram (OPG) was decreased after E. tenella challenge. Moreover, the lesion scores and histopathological cecum sections showed that recombinant L. plantarum can significantly relieve pathological damage in the cecum. The ACI was 170.89 in the recombinant L. plantarum group, which was higher than the 150.14 in the commercial
vaccine group.
CONCLUSIONS: These above results indicate that L. plantarum expressing RON2 improved humoral and cellular immunity and enhanced immunoprotection against E. tenella. The protective efficacy was superior to that of vaccination with the commercial live oocyst
vaccine. This study suggests that recombinant L. plantarum expressing the RON2 protein provides a promising strategy for
vaccine development against coccidiosis.