Rossi Andrea, Guarnaschelli Julio, Rial Analía, Moreno María, Rivera-Patron Mariana, Iriarte Andrés, Chabalgoity José A
Unidad Académica de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Front Immunol. 2025 May 20;16:1584168. doi: 10.3389/fimmu.2025.1584168. eCollection 2025.
is the causative agent of blackleg, a severe disease in cattle. Vaccination reduces disease incidence but the immune mechanisms that underlie vaccine-induced protection remain poorly understood, particularly the role of cellular immunity. In this study we characterized the humoral and cellular immune responses induced by a polyclostridial vaccine and assessed their correlation with protection against a challenge.
Eleven six month old Hereford calves, seronegative for anti antibodies, were randomized into vaccinated (n=8) and control (n=3) groups. Vaccinated animals received two doses of the vaccine at days 0 and 42-days. All animals were intramuscularly challenged with spores (8,000 LD50) at day 69 post vaccination and monitored for clinical outcomes. Blood samples were collected at pre-vaccination and pre- and post-challenge. Humoral responses were quantified by specific in-house developed ELISA. Cytokine gene expression was measured in whole-blood (RT-qPCR for IFN γ, TNF α, TGF β1, IL 4, IL 17A, IL 12B, IL 10) upon antigenic stimulation.
While vaccination protected cattle upon challenge and all animals survived, unvaccinated controls developed severe disease and died. Vaccination induced a strong specific antibody response although with inter-individual variation as well as a specific cytokine profile characterized by increased expression of IFN-γ, TGF-β1, and IL-4. Post-challenge, IFN-γ and IL-12B expression declined in vaccinated animals, but TGF-β1 persisted. High pre-challenge IgG, IFN-γ, and TGF-β1 were associated with protection, whereas increased IL-12B post-challenge was associated with disease severity.
These findings demonstrate a coordinated interplay between humoral and cellular immune responses in vaccine-induced protection, with IFN-γ emerging as a potential biomarker in conjunction with antibody titre. The study provides a deeper further understanding on the immune mechanisms underlying vaccine-mediated protection against and shall be relevant for the development of more effective vaccines.
是黑腿病的病原体，黑腿病是牛的一种严重疾病。疫苗接种可降低疾病发病率，但疫苗诱导保护作用的免疫机制仍知之甚少，尤其是细胞免疫的作用。在本研究中，我们对一种多梭菌疫苗诱导的体液免疫和细胞免疫反应进行了表征，并评估了它们与抵御攻击的保护作用之间的相关性。
将11头6月龄、抗抗体血清阴性的赫里福德犊牛随机分为疫苗接种组（n = 8）和对照组（n = 3）。接种疫苗的动物在第0天和第42天接受两剂疫苗。所有动物在接种疫苗后第69天肌肉注射芽孢（8000 LD50），并监测临床结果。在接种疫苗前以及攻击前和攻击后采集血样。通过内部开发的特异性ELISA定量体液反应。在抗原刺激后，在全血中测量细胞因子基因表达（针对IFNγ、TNFα、TGFβ1、IL4、IL17A、IL12B、IL10的RT-qPCR）。
虽然疫苗接种在攻击时保护了牛，所有动物都存活了下来，但未接种疫苗的对照组出现了严重疾病并死亡。疫苗接种诱导了强烈的特异性抗体反应，尽管存在个体差异，以及以IFN-γ、TGF-β1和IL-4表达增加为特征性的特异性细胞因子谱。攻击后，接种疫苗动物体内的IFN-γ和IL-12B表达下降，但TGF-β1持续存在。攻击前高IgG、IFN-γ和TGF-β1与保护作用相关，而攻击后IL-12B增加与疾病严重程度相关。
这些发现表明，在疫苗诱导的保护作用中，体液免疫和细胞免疫反应之间存在协同相互作用，IFN-γ与抗体滴度一起成为一种潜在的生物标志物。该研究为疫苗介导的抵御保护作用的免疫机制提供了更深入的理解，并且对于开发更有效的疫苗具有重要意义。
