Hope Jayne C, Khalid Hamza, Thom Michelle L, Howard Chris J, Shaw Darren J
Division of Infection and Immunity, The Roslin Institute, and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
Institute for Animal Health, Compton RG20 7NN, UK.
Pathogens. 2023 May 31;12(6):789. doi: 10.3390/pathogens12060789.
, the causative agent of bovine tuberculosis (bTB), is a globally prevalent pathogen with significant animal welfare, economic and public health impacts. In the UK, the control of bTB relies on detection via tuberculin skin tests with ancillary interferon gamma (IFN-γ) release assays, followed by culling infected animals. Vaccination with Bacille Calmette-Guérin (BCG) could be an important element of bTB control, and a number of studies have demonstrated its protective efficacy, particularly when young calves are vaccinated. Here, we compared immune responses and the protective efficacy of BCG in calves vaccinated within the first day of life and at three weeks of age. Significant protection from infection was observed in BCG-vaccinated calves compared to non-vaccinated, age-matched controls. No significant differences were shown between calves vaccinated at one day and at three weeks of age when assessing the protective efficacy of BCG (measured as a reduction in lesions and bacterial burden). Antigen-specific IFN-γ levels were similar between the BCG-vaccinated groups, but significantly different from the non-vaccinated control animals. Antigen-specific IFN-γ expression post-BCG vaccination was correlated significantly with protection from infection, whereas IFN-γ levels post-challenge correlated with pathology and bacterial burden. These results indicate that early-life vaccination with BCG could have a significant impact on infection and, therefore, bTB incidence, and they demonstrate that age, at least within the first month of life, does not significantly impact the protective effect of vaccination.
牛结核分枝杆菌是牛结核病（bTB）的病原体，是一种全球流行的病原体，对动物福利、经济和公共卫生有重大影响。在英国，bTB的控制依赖于通过结核菌素皮肤试验及辅助性γ干扰素（IFN-γ）释放试验进行检测，随后扑杀感染动物。卡介苗（BCG）接种可能是bTB控制的一个重要因素，多项研究已证明其保护效力，尤其是在对幼龄犊牛进行接种时。在此，我们比较了在出生第一天和三周龄时接种BCG的犊牛的免疫反应和保护效力。与未接种、年龄匹配的对照相比，接种BCG的犊牛对感染有显著的保护作用。在评估BCG的保护效力（以病变和细菌负荷的减少来衡量）时，出生一天和三周龄接种的犊牛之间未显示出显著差异。接种BCG的组之间抗原特异性IFN-γ水平相似，但与未接种的对照动物有显著差异。接种BCG后抗原特异性IFN-γ表达与对感染的保护显著相关，而攻毒后IFN-γ水平与病理学和细菌负荷相关。这些结果表明，早期接种BCG可能对感染以及因此对bTB发病率有重大影响，并且它们证明年龄，至少在出生后的第一个月内，不会显著影响接种疫苗的保护效果。
