Universidade Federal de Viçosa - UFV, Departamento de Veterinária, Laboratório de Biologia e Controle de Hematozoários e Vetores, Instituto de Biotecnologia Aplicada à Agropecuária - BIOAGRO, Viçosa - MG, CEP 36570-900, Brasil.
Universidade Federal de Viçosa - UFV, Departamento de Veterinária, Laboratório de Biologia e Controle de Hematozoários e Vetores, Instituto de Biotecnologia Aplicada à Agropecuária - BIOAGRO, Viçosa - MG, CEP 36570-900, Brasil.
Ticks Tick Borne Dis. 2020 Sep;11(5):101461. doi: 10.1016/j.ttbdis.2020.101461. Epub 2020 May 12.
is the most important ectoparasite of livestock in tropical and subtropical areas around the world. Research focused on developing an efficient vaccine for cattle tick control is a high priority. The aim of this study was to evaluate the rSBm7462® peptide (Bm86-B and T cell epitopes) regarding its properties of immunogenicity, protective effect in cattle and efficacy against R. microplus. This peptide was produced by a fermentative process in the yeast culture system of Komagataella (Pichia) pastoris strain Km 71. The vaccination assay was conducted in a tick-free area using non-splenectomised Holstein Friesian calves, separated into immunisation and control groups. These animals individually received the recombinant peptide and the inoculum without peptide using saponin as an adjuvant at three time points. The calves were challenged 21 days after the last immunisation using 4500 larvae per animal. An indirect ELISA was used to identify the IgG kinetics of serum samples from the calves studied. The qPCR was performed to determine the cytokine gene expression from the total RNA of the cultured PBMCs. Histomorphometry of the germinal centres (GCs) was performed measuring slides with haematoxylin-eosin staining of surgically removed lymph nodes from immunised calves. The antibody response showed a significant induction of high-affinity IgGs in calves immunised with the recombinant peptide in comparison to the controls. The kinetics of antibodies in immunised calves showed a significant increase during the experiment. This increase in high-affinity IgGs correlated with a gradual increase of the GC diameter following each peptide vaccination. Cytokine expression profiles demonstrating an adaptive immune response in calves immunised with rSBm7462® confirmed the T-dependent response. Vaccine efficacy was calculated at 72.4 % following the analysis and fecundity of collected adult female ticks, compared between control and vaccinated groups. These findings demonstrate that this new recombinant peptide is an option for control of R. microplus infestations.
是全球热带和亚热带地区牲畜最重要的外寄生虫。因此，研究重点是开发一种有效的牛蜱控制疫苗。本研究的目的是评估 rSBm7462®肽（Bm86-B 和 T 细胞表位）的免疫原性、对牛的保护作用和抗 R. microplus 的效果。该肽由毕赤酵母（Komagataella）发酵工艺生产，Km 71 株系。接种试验在无蜱地区进行，使用未行脾切除术的荷斯坦弗里生小牛，分为免疫组和对照组。这些动物单独接受重组肽和无肽接种物，并用皂素作为佐剂在三个时间点接种。最后一次免疫接种后 21 天，每只动物用 4500 只幼虫进行攻虫。使用间接 ELISA 来鉴定所研究小牛血清样品中的 IgG 动力学。使用 qPCR 来确定来自培养 PBMCs 的细胞因子基因表达。通过对免疫小牛手术切除的淋巴结进行苏木精-伊红染色的切片进行生发中心（GCs）的组织形态计量学分析。与对照组相比，用重组肽免疫的小牛抗体反应显示出高亲和力 IgG 的显著诱导。免疫小牛的抗体动力学在实验过程中呈显著增加。这种高亲和力 IgG 的增加与每次肽接种后 GC 直径的逐渐增加相关。rSBm7462® 免疫小牛的细胞因子表达谱证明了适应性免疫反应，证实了 T 依赖性反应。通过分析和收集的成年雌性蜱的生殖力，计算疫苗效力为 72.4%，与对照组和免疫组相比。这些发现表明，这种新的重组肽是控制 R. microplus 感染的一种选择。
