In vitro models to study attachment and invasion of Helicobacter pylori
In vitro models to study attachment and invasion of Helicobacter pylori
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DOI：
10.1111/j.1749-6632.1996.tb52983.x
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发表时间：
1996-01-01
期刊：
影响因子：
--
通讯作者：
Quinn, FD
中科院分区：
文献类型：
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作者：
Birkness, KA;Gold, BD;Quinn, FD
直到最近，幽门杆菌还是一种未知的生物，现在被认为是最常见的人类病原体之一。除了在感染者中引起慢性活动性胃炎外，重要证据还表明，长期感染可能导致消化性溃疡疾病，甚至可能导致胃癌。该生物对胃粘膜表现出明显的组织特异性。食入后，胃门螺杆菌定植在胃上皮上的黏液层，随后附着在上皮细胞表面，通常靠近细胞紧密连接。细菌繁殖，细胞间侵入，内化，毒素的细化，以及刺激强烈的炎症和免疫反应。慢性活动性胃炎是宿主胃黏膜对幽门螺旋杆菌定植的炎症反应的结果。虽然这种急性和慢性的炎症反应有助于疾病的发展，但它并不能有效地根除病菌。H. pylon也引起强烈的体液和细胞免疫反应，但几乎没有证据表明两者都是成功的自发清除生物体。在组织病理学研究中，H. pylon侵袭组织的报道很少；在固有层内可见少量细菌，但侵袭粘膜是罕见的。炎症细胞的吸引和激活更可能是对胃上皮细胞产生的细胞因子的反应。确实发生的细菌入侵可能会使细菌抗原呈递给宿主免疫系统，或者可能为生物体提供对化疗药物的保护，从而导致根除困难。尽管许多问题仍未得到解答，但很明显，幽门螺旋杆菌与胃上皮之间的初始相互作用对于理解由该生物引起的疾病谱系的发病机制至关重要。我们利用AGS人胃癌组织培养细胞单层，通过活细胞计数和电镜观察，研究了H. pylon的细胞关联和内化。此外，我们还开发了一种新的组织培养双层模型3；它由人微血管内皮细胞（HMEC-1）和AGS或小鼠肝上皮细胞（NCTC）组成，由微孔膜隔开。该系统允许观察附着和通过细胞层的细胞内或细胞间通道，以及能够通过两个细胞层进入下面空间的细菌计数。双层模型比单层模型更接近细菌在人类宿主体内可能遇到的组织。当H. pylon加入到这些双层结构中时，光镜和电子显微镜显示感染的进展，从第一次与上皮细胞顶端表面的亲密附着到穿过上皮细胞、膜和内皮细胞之间并进入内皮下间隙。
Helicobacterpylon, until recently an unknown organism, is now recognized as one of the most common human pathogens. In addition to causing chronic active gastritis in infected individuals, significant evidence also indicates that long-term infection may lead to peptic ulcer disease and perhaps to gastric cancer. The organism exhibits marked tissue specificity for the gastric mucosa. Following ingestion, H. pylon colonizes the mucous layer overlying the gastric epithelium and subsequently attaches to the epithelial cell surface, often in close proximity to the cellular tight junctions. Bacterial multiplication, invasion between cells, internalization, elaboration of toxins, and stimulation of potent inflammatory and immune responses follow. The chronic active gastritis seen in this disease is a consequence of the inflammatory responses mounted by the host gastric mucosa against H. pylon colonization. Although this inflammatory reaction, which is both acute and chronic, contributes to the disease process, it is not effective in eradicating the organism. H. pylon also elicits vigorous humoral and cellular immune responses, but there is little evidence to suggest that either is successful in spontaneous clearance of the organism.'In histopathologic studies, tissue invasion by H. pylon is seldom reported; small numbers of bacteria have been seen within the lamina propria, but mucosal invasion is rare. The attraction and activation of inflammatory cells are more likely a response to cytokines produced by gastric epithelial cells. The bacterial invasion that does occur may allow presentation of bacterial antigens to the host immune system or may offer the organism protection from chemotherapeutic agents, leading to difficulty in eradication. 2 Although many questions remain unanswered, it is clear that the initial interaction between H. pylon and the gastric epithelium is of critical importance in understanding the pathogenesis of the disease spectrum caused by this organism. We have used AGS human gastric carcinoma tissue culture cell monolayers to study cell association and internalization of H. pylon using both viable cell count and electron microscopy. In addition, we have developed a novel tissue culture bilayer model3; it consists of human microvascular endothelial cells (HMEC-1) and AGS or mouse hepatic (NCTC) epithelial cells separated by a microporous membrane. The system allows observation of attachment and intra-or intercellular passage through the cell layers as well as enumeration of bacteria able to pass through both cell layers into the space below. The bilayer model resembles more closely than a monolayer the tissue that the bacterium may encounter in the human host. When H. pylon is added to these bilayers, light and electron microscopy shows the progression of infection from the first intimate attachment to the apical surface of the epithelial cells to passage through and between the epithelial cells, membrane, and endothelial cells and into the subendothelial space.