Navigation Links
Helicobacter pylori can multiply in autophagic vesicles

Helicobacter pylori, a Gram-negative, flagellated, microaerophilic bacterium, can selectively colonize in the human stomach. Its infection is widespread throughout the world, and is present in about 50% of the global human population with 80% in developing countries and 20-50% in industrialized countries. Infection of the stomach with H. pylori induces a local immune response with infiltration of the mucosa by macrophages, neutrophils and lymphocytes. Although the innate and adaptive immune responses are activated, the bacterium is rarely eliminated and infections can last for decades if left untreated. Most infections are asymptomatic, but overt diseases can occur in 10-20 % of infected individuals. The disease spectrum ranges from gastritis to peptic ulceration disease. A long-term chronic infection will increase the risk to gastric adenocarcinoma and mucosa-associated lymphoid-tissue lymphoma. It has been classified as a class I carcinogen by the WHO. Despite intensive studies, and the award of the 2005 Nobel Prize in Physiology for the discovery of the bacterium H. pylori by Robin Warren and Barry Marshall, our understanding of H. pylori-infection-caused disease is still limited. H. pylori has evolved several mechanisms to increase its adherence and persistence in the host. In addition, it must also evade immune clearance. Elimination of H. pylori by phagocytes is inefficient because H. pylori exhibits several virulence factors to evade opsonization, retard phagocytosis, and disrupt membrane trafficking and phagosome maturation after internalization of the microorganism.

In the February 2009 issue of Experimental Biology and Medicine researchers at the National Cheng Kung University, Tainan, Taiwan, have reported a novel phenomenon involving autophagosome formation induced by H. pylori infection and subsequent adoption of these autophagic vesicles by H. pylori for replication in macrophages. The fate of H. pylori is dependent on the strains (isolates) as well as the host macrophages used. Several clinical isolates of H. pylori from Taiwanese patients, but not standard strains, can multiply in the double-layered vesicles of macrophages. The senior author, Dr. Huan-Yao Lei stated that "The autophagy induction by H. pylori is not only found in macrophages, but also in dendritic cells and gastric epithelial cells". This new finding has several implications for the life cycle of H. pylori in the host. H. pylori can be considered as a kind of intracellular microorganism because it can invade host cells to undergo replication within the autophagosome. The bacterium's residence inside infected cells not only increases its resistance to antibiotic treatment, but also avoids neutralization by anti-H. pylori antibodies. In view of the critical role of dendritic cells in presenting H. pylori antigen to initiate the immune response, it is possible that H. pylori-infected dendritic cells induce an inadequate immune response to H. pylori infection that might hinder the clearance of this bacterium. Alternatively, the various immunopathogenesis during the H. pylori-caused diseases might be caused by an unbalanced Th-1 or Th2-mediated response post infection. Finally, the micro-heterogeneity of Taiwanese H. pylori isolates used in this study provides an important hint as to why this microorganism causes so broad a spectrum of diseases. Dr. Steven R. Goodman, Editor-in-Chief of Experimental Biology and Medicine stated "This study also has potential implications for new anti-H. pylori drugs that target the enhancement of autophagy. Dr. Lei and his co-workers have provided an important contribution to our understanding of H. pylori infection."


Contact: Dr. Huan-Yao Lei
Society for Experimental Biology and Medicine

Related medicine news :

1. How do Lactobacilli treat Helicobacter pylori-related diseases?
2. Helicobacter pylori inhibits intercellular communication of cultured gastric cells
3. Gastric juice for diagnosis of H. pylori infection in patients on proton pump inhibitors
4. How is H pylori adhesion to gastric cells associated with MUC1 mucin VNTR size?
5. A low prevalence of H pylori in HIV-positive patients
6. Bernadette Peters Joins Board of Directors of Standing Tall, Innovative Program for Multiply Disabled Children
7. Extracts of catfish caught in polluted waters cause breast cancer cells to multiply
Post Your Comments:
(Date:11/30/2015)... ... November 30, 2015 , ... Insightra Medical, Inc. and Novus ... technology for soft tissue repair in the US via Insightra’s national direct sales ... mesh intended to support and reinforce soft tissue for 6-9 months before absorbing ...
(Date:11/30/2015)... ... 30, 2015 , ... SIMmersion’s ability to present dynamic scenarios ... of the future. To reach an audience of key visionaries and reformers in ... Chicago, organized by the American Medical Association. , AMA President Steven Stack, ...
(Date:11/30/2015)... ... November 30, 2015 , ... ... enterprise Time and Attendance/Workforce Management cloud-based solutions, announced today that it has ... competencies in the Application Development, demonstrating a “best-in-class” ability and commitment to ...
(Date:11/30/2015)... November 30, 2015 (PRWEB) , ... ... ... and Winscribe are pleased to announce their strategic partnership at the Radiological ... consultants, SpeechCheck, Inc., and Winscribe, global providers of cutting-edge dictation and speech-enabled ...
(Date:11/30/2015)... ... 30, 2015 , ... World Patent Marketing , a ... household invention that provides an economical and easy way of gaining customized curtains. ... at 2.6%," says Scott Cooper, CEO and Creative Director of World Patent Marketing. ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... , November 26, 2015 /PRNewswire/ ... --> adds "Global ... and "Investigation Report on China Repaglinide ... 2021 forecasts data and information to ... . --> ...
(Date:11/26/2015)... , Nov. 26, 2015 Research and ... of the "2016 Future Horizons and Growth ... Market: Supplier Shares, Country Segment Forecasts, Competitive Intelligence, ... --> --> ... of the Italian therapeutic drug monitoring market, including ...
(Date:11/26/2015)... November 26, 2015 ... addition of the  "2016 Future Horizons ... Cell Surface Marker Testing Market: Supplier ... to their offering.  --> ... of the  "2016 Future Horizons and ...
Breaking Medicine Technology: