Stabel J R, Waters W R, Bannantine J P, Palmer M V
USDA-ARS, National Animal Disease Center, Ames, IA, USA.
Clin Vaccine Immunol. 2013 Jun;20(6):848-57. doi: 10.1128/CVI.00051-13. Epub 2013 Apr 3.
The cross-reactivity of mycobacterial antigens in immune-based diagnostic assays has been a major concern and a criticism of the current tests that are used for the detection of paratuberculosis. In the present study, Mycobacterium avium subsp. paratuberculosis recombinant proteins were evaluated for antigenic specificity compared to a whole-cell sonicate preparation (MPS). Measures of cell-mediated immunity to M. avium subsp. paratuberculosis antigens were compared in calves inoculated with live M. avium subsp. paratuberculosis, M. avium subsp. avium (M. avium), Mycobacterium kansasii, or Mycobacterium bovis. Gamma interferon (IFN-γ) responses to MPS were observed in all calves that were exposed to mycobacteria compared to control calves at 4 months postinfection. Pooled recombinant M. avium subsp. paratuberculosis proteins also elicited nonspecific IFN-γ responses in inoculated calves, with the exception of calves infected with M. bovis. M. avium subsp. paratuberculosis proteins failed to elicit antigen-specific responses for the majority of immune measures; however, the expression of CD25 and CD26 was upregulated on CD4, CD8, gamma/delta (γδ) T, and B cells for the calves that were inoculated with either M. avium subsp. paratuberculosis or M. avium after antigen stimulation of the cells. Stimulation with MPS also resulted in the increased expression of CD26 on CD45RO(+) CD25(+) T cells from calves inoculated with M. avium subsp. paratuberculosis and M. avium. Although recombinant proteins failed to elicit specific responses for the calves inoculated with M. avium subsp. paratuberculosis, the differences in immune responses to M. avium subsp. paratuberculosis antigens were dependent upon mycobacterial exposure. The results demonstrated a close alignment in immune responses between calves inoculated with M. avium subsp. paratuberculosis and those inoculated with M. avium that were somewhat disparate from the responses in calves infected with M. bovis, suggesting that the biology of mycobacterial infection plays an important role in diagnosis.
分枝杆菌抗原在基于免疫的诊断检测中的交叉反应性一直是主要关注点，也是对当前用于检测副结核病的检测方法的一项批评。在本研究中，对鸟分枝杆菌副结核亚种重组蛋白与全细胞超声裂解物制剂（MPS）相比的抗原特异性进行了评估。在接种了活的鸟分枝杆菌副结核亚种、鸟分枝杆菌、堪萨斯分枝杆菌或牛分枝杆菌的犊牛中，比较了对鸟分枝杆菌副结核亚种抗原的细胞介导免疫指标。与未感染的对照犊牛相比，在感染后4个月时，所有接触分枝杆菌的犊牛均观察到对MPS的γ干扰素（IFN-γ）反应。除感染牛分枝杆菌的犊牛外，混合的鸟分枝杆菌副结核亚种重组蛋白也在接种的犊牛中引发了非特异性IFN-γ反应。鸟分枝杆菌副结核亚种蛋白未能引发大多数免疫指标的抗原特异性反应；然而，对于接种了鸟分枝杆菌副结核亚种或鸟分枝杆菌的犊牛，在细胞抗原刺激后，CD4、CD8、γδ T和B细胞上CD25和CD26的表达上调。用MPS刺激也导致接种了鸟分枝杆菌副结核亚种和鸟分枝杆菌的犊牛的CD45RO(+) CD25(+) T细胞上CD26的表达增加。尽管重组蛋白未能引发接种鸟分枝杆菌副结核亚种的犊牛的特异性反应，但对鸟分枝杆菌副结核亚种抗原的免疫反应差异取决于分枝杆菌暴露情况。结果表明，接种鸟分枝杆菌副结核亚种的犊牛与接种鸟分枝杆菌的犊牛的免疫反应密切一致，这与感染牛分枝杆菌的犊牛的反应有些不同，表明分枝杆菌感染生物学在诊断中起重要作用。
