结核分枝杆菌感染实验模型

结核分枝杆菌是引起人结核病的主要病原,全世界约有1/3人口感染结核分枝杆菌。尽管该病原可感染并引起许多动物疾病,但人类是其中心宿主。为研究结核分枝杆菌的致病机理及宿主对本病原的保护性和免疫病理学反应,选择合适的动物模型非常必要。本文阐述了结核病研究中常用的实验模型及各种模型的优缺点。实验模型的合理应用将促进我们对结核病的认识,从中获取的资料将有助于我们发现更好的预防和治疗方案。     

滴鼻途径建立鼠结核病模型的探讨

目的 探讨滴鼻途径建立BALB/C小鼠结核分枝杆菌感染的模型的可行性.方法 人型Mtb H_(37)Rv标准株经腹腔接种小鼠,取小鼠腹腔冲洗液100 μl接种改良罗-琴氏培养基.刮取上述培养基上生长4周已恢复毒力的结核分枝杆菌H_(37)Rv标准株,加0.05%Tween80生理盐水磨菌制成悬液,菌落计数,计数后稀释悬液为5×10~3 CFU/50 μl、5×10~4 CFU/50 μl、5×10~5 CFU/50 μl及50 μl生理盐水分别感染4组Balb/c小鼠,制作结核分枝杆菌感染模型.结果 滴鼻感染小鼠4周后,所有小鼠肺、脾组织中均可见抗酸阳性菌,在感染小鼠肺、脾组织匀浆均培养出Mtb.肺组织病理改变明显,正常肺泡结构消失,以充血实变、淋巴细胞、巨噬细胞浸润为主,增生性改变不明显,未见明显的组织坏死.脾组织病理改变主要是巨噬细胞和淋巴细胞增生.结论 滴鼻感染途径建立小鼠结核病模型简便、可行,为进一步研究开发重组BCG疫苗对鼠结核病的防治打下良好的基础. 0~4 CFU/50 μl、5×10~5 CFU/50 μl及50 μl生理盐水分别感染4组Balb/c小鼠,制作结核分枝杆菌感染模型.结果 滴鼻感染小鼠 周后,所有小鼠肺、脾组织中均可见抗酸阳性菌,在感染小鼠肺、脾组织匀浆均培养出Mtb.肺组织病理改变明显,正常肺泡结构消失,以充血实变、淋巴细胞、巨噬细胞浸润为主,增生性改变不明显,未见明显的组织坏死.脾组织病理改变主要是巨噬细胞和淋巴细胞增生.结论 滴鼻感染途径建立小鼠结核病模型简便、可行,为进一步研究开发重组BCG疫苗对鼠结核病的防治打下良好的基础. 0~4 CFU/50 μl、5×10~5 CFU/50 μl及50 μl生理盐水分别感染4组Balb/c     

Tuberculosis patients co-infected with Mycobacterium bovis and Mycobacterium tuberculosis in an urban area of Brazil

In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials.     

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.     

人结核分枝杆菌特异性核酸探针制备及结核病PCR检测技术的初步临床应用

采用人结核分枝杆菌(Mycobacterium tuberculosis TB)染色体DNA为模板,选择位于插入片段IS6110中884～865和568～588碱基对处的两个片段为引物,扩增出317bp的特异性片段．将其克隆进pUCl9载体。酶切图谱分析和DNA序列测定证实为目的片段。该片段经DIG标记,分别与11种分枝杆菌DNA进行Southern杂交,结果证明只与人型复合分枝杆菌发生杂交反应。利用该对引物建立的PcR检测拄术对74份结核病痰液标本进行检测,并与临床细菌快速培养结果相比较,发现48份临床阳性均为PcR阳性,在26份临床阴性标本中亦发现11份PCR检测阳性。将标本PCR产物与克隆探针进行杂交,显示两者结果完全一致。说明PCR检测体系结果可靠,其灵敏度明显高于目前临床所采用的方法,可作为一种常规技术用于结核病的临床检测。     

Interactions of 5-deazapteridine Derivatives with Mycobacterium tuberculosis and with Human Dihydrofolate Reductases

Abstract

There are major differences between the structures of human dihydrofolate reductase (hDHFR) and Mycobacterium tuberculosis dihydrofolate reductase (mtDHFR). These differences may allow us to design more selective mtDHFR inhibitors. In this paper we study the reactions of six different compounds derived from 5-deazapteridine with human and bacterial enzymes. Results suggest that the addition of hydrophobic groups to the aminophenyl ring would increase mtDHFR-inhibitor affinity and selectivity.     

结核感染T细胞斑点试验联合血清ADA、SAA、CA125对活动性肺结核诊断及治疗转归的评估价值

摘要 目的：探讨结核感染T细胞斑点试验（T-SPOT.TB）联合血清腺苷脱氨酶（ADA）、淀粉样蛋白A（SAA）、糖类抗原125（CA125）对活动性肺结核（APTB）诊断及治疗转归的评估价值。方法：选取2021年10月至2022年10月湖南省胸科医院收治的137例APTB患者（APTB组）和80例非APTB患者（对照组）,所有APTB患者接受常规抗结核治疗,根据治疗后转归情况分为转归组（92例）和未转归组（45例）。治疗前进行T-SPOT.TB,并检测血清ADA、SAA、CA125水平。受试者工作特征（ROC）曲线分析T-SPOT.TB联合血清ADA、SAA、CA125诊断APTB和预测治疗转归的效能。结果：APTB组T-SPOT.TB阳性率,血清ADA、SAA、CA125水平高于对照组（P＜0.05）。未转归组T-SPOT.TB阳性率,血清ADA、SAA、CA125水平高于转归组（P＜0.05）。T-SPOT.TB联合血清ADA、SAA、CA125诊断APTB以及预测其治疗转归的曲线下面积（AUC）分别为0.917、0.833,高于单一指标。结论：APTB患者T-SPOT.TB阳性率增加,血清ADA、SAA、CA125水平增高,与抗结核治疗后转归不良有关,T-SPOT.TB联合血清ADA、SAA、CA125在APTB诊断和治疗转归评估中具有较高价值。