BACKGROUND Melioidosis is endemic in Southeast Asia and Northern Australia and is caused by the Gram-negative, facultative intracellular pathogen Burkholderia pseudomallei. Diagnosis of melioidosis is often difficult because of the protean clinical presentation of the disease, and it may mimic other diseases, such as tuberculosis. There are many different strains of B. pseudomallei that have been isolated from patients with melioidosis, but it was not clear if they could cause a similar disease in a chronic BALB/c murine model of melioidosis. Hence, we wanted to examine chronically infected mice exposed to different strains of B. pseudomallei to determine if there were differences in the host immune response to the pathogen. RESULTS We identified common host immune responses exhibited in chronically infected BALB/c mice, although there was some heterogeneity in the host response in chronically infected mice after exposure to different strains of B. pseudomallei. They all displayed pyogranulomatous lesions in their spleens with a large influx of monocytes/macrophages, NK cells, and neutrophils identified by flow cytometry. Sera from chronically infected mice by ELISA exhibited elevated IgG titers to the pathogen, and we detected by Luminex micro-bead array technology a significant increase in the expression of inflammatory cytokines/chemokines, such as IFN-γ, IL-1α, IL-1β, KC, and MIG. By immunohistochemical and in situ RNA hybridization analysis we found that the increased expression of proinflammatory cytokines (IL-1α, IL-1β, TNF-α, IFN-γ) was confined primarily to the area with the pathogen within pyogranulomatous lesions. We also found that cultured splenocytes from chronically infected mice could express IFN-γ, TNF-α, and MIP-1α ex vivo without the need for additional exogenous stimulation. In addition by flow cytometry, we detected significant amounts of intracellular expression of TNF-α and IFN-γ without a protein transport blocker in monocytes/macrophages, NK cells, and neutrophils but not in CD4+ or CD8+ T cells in splenocytes from chronically infected mice. CONCLUSION Taken together the common features we have identified in chronically infected mice when 10 different human clinical strains of B. pseudomallei were examined could serve as biomarkers when evaluating potential therapeutic agents in mice for the treatment of chronic melioidosis in humans.

中文翻译：

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当比较假人伯克霍尔德氏菌的多个人类株时，TNF-α和IFN-γ表达的失调是在慢性感染的类拟osis病小鼠模型中常见的宿主免疫应答。

背景技术类胡osis病在东南亚和北澳大利亚是地方性的，并且是由革兰氏阴性，兼性细胞内病原体伯克霍尔德菌假mallei引起的。由于该病的蛋白质临床表现，其诊断通常很困难，并且可能模仿其他疾病，例如结核病。从类鼻疽病患者中分离出了许多不同的假苹果芽孢杆菌菌株，但尚不清楚它们是否会在慢性BALB / c鼠类疱疹小鼠模型中引起类似的疾病。因此，我们想检查暴露于不同伪假单胞菌菌株的慢性感染小鼠，以确定宿主对病原体的免疫反应是否存在差异。结果我们确定了在慢性感染的BALB / c小鼠中表现出的常见宿主免疫反应，虽然暴露于不同菌株的假双歧杆菌后，慢性感染小鼠的宿主反应存在某些异质性。他们都在脾脏中出现了肉芽肿性病变，并有大量单核细胞/巨噬细胞，NK细胞和中性粒细胞通过流式细胞仪鉴定。ELISA法检测慢性感染小鼠的血清对病原体的IgG滴度升高，我们通过Luminex微珠阵列技术检测到炎性细胞因子/趋化因子（如IFN-γ，IL-1α，IL-1β）的表达显着增加，KC和MIG。通过免疫组织化学和原位RNA杂交分析，我们发现促炎性细胞因子（IL-1α，IL-1β，TNF-α，IFN-γ）表达的增加主要局限于病原体位于脓性肉芽肿病变内的区域。我们还发现，来自慢性感染小鼠的脾细胞可以离体表达IFN-γ，TNF-α和MIP-1α，而无需额外的外源刺激。此外，通过流式细胞仪，我们在慢性感染小鼠脾细胞的单核细胞/巨噬细胞，NK细胞和嗜中性粒细胞中检测到大量的TNF-α和IFN-γ的细胞内表达，而没有蛋白转运阻滞剂，但在脾细胞的CD4 +或CD8 + T细胞中未检测到。结论总结了我们在慢性感染小鼠中鉴定出的共同特征，当评估10种不同的人类临床假双歧杆菌时，它们可以作为生物标记物，用于评估小鼠中潜在的人类慢性类oid病的治疗剂。和MIP-1α离体，无需其他外源刺激。此外，通过流式细胞仪，我们在慢性感染小鼠脾细胞的单核细胞/巨噬细胞，NK细胞和嗜中性粒细胞中检测到大量的TNF-α和IFN-γ的细胞内表达，而没有蛋白转运阻滞剂，但在脾细胞的CD4 +或CD8 + T细胞中未检测到。结论总结了我们在慢性感染小鼠中鉴定出的共同特征，当评估10种不同的人类临床假双歧杆菌时，它们可以作为生物标记物，用于评估小鼠中潜在的人类慢性类oid病的治疗剂。和MIP-1α离体，无需其他外源刺激。此外，通过流式细胞仪，我们在慢性感染小鼠脾细胞的单核细胞/巨噬细胞，NK细胞和嗜中性粒细胞中检测到大量的TNF-α和IFN-γ的细胞内表达，而没有蛋白转运阻滞剂，但在脾细胞的CD4 +或CD8 + T细胞中未检测到。结论总结了我们在慢性感染小鼠中鉴定出的共同特征，当评估10种不同的人类临床假双歧杆菌时，它们可以作为生物标记物，用于评估小鼠中潜在的人类慢性类oid病的治疗剂。和嗜中性粒细胞，但不在慢性感染小鼠脾细胞的CD4 +或CD8 + T细胞中。结论总结了我们在慢性感染小鼠中鉴定出的共同特征，当评估10种不同的人类临床假双歧杆菌时，它们可以作为生物标记物，用于评估小鼠中潜在的人类慢性类oid病的治疗剂。和嗜中性粒细胞，但不在慢性感染小鼠脾细胞的CD4 +或CD8 + T细胞中。结论总结了我们在慢性感染小鼠中鉴定出的共同特征，当评估10种不同的人类临床假双歧杆菌时，它们可以作为生物标记物，用于评估小鼠中潜在的人类慢性类oid病的治疗剂。