牛支原体是北美野牛(Bisonbison)的重要病原体,与呼吸和生殖疾病的高发病率和高死亡率相关。尽管对野牛健康有重大负面影响,对疾病的动力学和宿主对感染的免疫反应知之甚少。为了解决这些问题,一组野牛小牛被创建并连续采样5次,每2-3个月一次,在12个月的时间里。在每个采样期收集鼻拭子样品并通过PCR测试牛分枝杆菌的存在。还收集血清样品并使用商业和内部ELISA评估牛分枝杆菌特异性抗体。总的来说,19/41野牛(46.3%)的PCR检测呈阳性,31/41(75.6%)为血清阳性。在研究过程中,PCR阳性鼻拭子的频率和ELISA评分降低,尽管血清样本在最终PCR检测阳性后至少6个月保持阳性。根据内部ELISA的结果将野牛分组为高反应者(n=7),低反应者(n=5),和血清阴性组(n=7)。与低反应者和血清阴性组相比,高反应者组的牛支原体特异性IgG抗体水平显着升高。3/5采样周期的差异有统计学意义。在高反应者组中观察到IgG2水平增加的趋势。高的总IgG应答与鼻拭子的阳性PCR测试的下降相关。这些数据提供了强体液应答是有益的并且可能涉及从野牛中清除牛分枝杆菌的证据。
Mycoplasma bovis (M. bovis) is an important pathogen of American
bison (
Bison bison), associated with high morbidity and mortality epizootics of respiratory and reproductive disease. Despite the significant negative impact on
bison health, little is known about the kinetics of disease and the host immune response to infection. To address these questions, a cohort of
bison calves was created and serially sampled 5 times, once every 2-3 mo, over a 12-mo period. At each sampling period nasal swab samples were collected and tested by PCR for the presence of M. bovis. Serum samples were also collected and assessed for M. bovis-specific antibodies using both a commercial and an in-house ELISA. Overall, 19/41
bison (46.3%) had positive PCR tests, and 31/41 (75.6%) were seropositive. Over the course of the study, the frequency of PCR-positive nasal swabs and the ELISA scores decreased, although serum samples remained positive for at least 6 mo following the final positive PCR test.
Bison were grouped according to results from the in-house ELISA into high-responder (n=7), low-responder (n=5), and seronegative (n=7) groups. M. bovis-specific IgG antibody levels were significantly elevated in the high-responder group compared to the low-responder and seronegative groups. The differences were statistically significant for 3/5 sampling periods. A trend toward increased IgG2 levels was observed in the high-responder group. High total IgG responses correlated with a decline in positive PCR tests from nasal swabs. These data provide evidence that a strong humoral response is beneficial and is probably involved in the clearance of M. bovis from bison.