In the present study, calves were infected with Mycobacterium avium subsp. paratuberculosis (MAP), Mycobacterium avium subsp. avium (M. avium), Mycobacterium kansasii (M. kansasii), or Mycobacterium bovis (M. bovis) to determine differences in cellular immunity. Comparative cellular responses were assessed upon stimulation of cells with mycobacterial whole cell sonicates respective of each infection group. Antigen-specific whole blood interferon gamma (IFN-γ) responses were observed in all infection groups compared to noninfected control calves, however, responses were more robust for M. bovis calves. Upon antigen stimulation of PBMCs, secretion of IFN-γ and IL-10 was higher for M. bovis calves compared to other infection groups. In contrast, IL-12 secretion was lower for M. bovis calves compared to MAP infected calves. Within the total PBMC population, higher numbers of CD4+, CD8+, and γδ TCR + T cells were observed for MAP and M. avium calves compared to M. bovis calves. This aligned with higher expression of CD26 on these subpopulations for MAP and M. avium calves, as well. In contrast, greater expression of CD25 was observed on CD4+ and γδ TCR + T cells and natural killer cells for M. bovis calves. Overall, similarities in cellular immune responses were observed between the closely related MAP and M. avium during infection of calves. In contrast, significant differences were noted between calves infected with MAP and M. bovis. This suggests that host immune responses to different mycobacteria may impact interpretation of diagnostic tools based upon their cellular immunity.

在本研究中，小牛感染了鸟分枝杆菌亚种。副结核病(MAP)，鸟分枝杆菌亚种。avium ( M. avium )、堪萨斯分枝杆菌( M. kansasii ) 或牛分枝杆菌( M. bovis ) 以确定细胞免疫的差异。在用每个感染组各自的分枝杆菌全细胞超声刺激细胞时评估比较细胞反应。与未感染的对照小牛相比，在所有感染组中都观察到了抗原特异性全血干扰素γ（IFN-γ）反应，但是，牛分枝杆菌的反应更加强烈小牛。在 PBMC 的抗原刺激后，与其他感染组相比，牛分枝杆菌小牛的 IFN-γ 和 IL-10 分泌更高。相比之下，与 MAP 感染的小牛相比，牛分枝杆菌小牛的IL-12 分泌较低。在总 PBMC 群体中，与牛分枝杆菌小牛相比，MAP 和鸟分枝杆菌小牛的 CD4+、CD8+ 和γδ TCR + T 细胞数量更多。这与 MAP 和M. avium小牛的这些亚群上 CD26 的更高表达一致。相比之下，在 CD4+ 和 γ δ TCR + T 细胞以及牛分枝杆菌的自然杀伤细胞上观察到 CD25 的更高表达小牛。总体而言，在小牛感染期间，在密切相关的 MAP 和M. avium之间观察到细胞免疫反应的相似性。相比之下，感染 MAP 的小牛和牛分枝杆菌之间存在显着差异。这表明宿主对不同分枝杆菌的免疫反应可能会影响基于其细胞免疫的诊断工具的解释。