Affiliation:
1. Department of Medical Microbiology and Immunology, Ruhr-University Bochum, Federal Republic of Germany.
Abstract
Despite the induction of an immunological reaction, Helicobacter pylori-associated gastritis is a chronic disease, suggesting that this microbe can evade the host immune defense. Previous studies by our group showed that H. pylori suppresses the in vitro proliferative response of human mononuclear cells to mitogens and antigens. Here we demonstrate that the antiproliferative activity of H. pylori also affects the proliferation of various mammalian cell lines (U937, Jurkat, AGS, Kato-3, HEP-2, and P388D1). This effect is detectable in the first 16 h of incubation and maximal between 24 and 48 h. In addition, the presence of H. pylori significantly diminished the protein synthesis of cells in the first 6 h of incubation, comparable to the results with cycloheximide and diphtheria toxin. The urease enzyme, the cagA gene product, and the vacuolizing cytotoxin of H. pylori were excluded as causative agents of the antiproliferative effect by using isogenic knockout mutant strains. The inhibitory effect was not due to a lytic activity of this bacterium. The results reported here indicate that the responsible factor is a protein with an apparent native molecular mass of 100 +/- 10 kDa. Our work implicates the presence of a protein factor in H. pylori (termed PIP [for proliferation-inhibiting protein]) with antiproliferative activity for mammalian cells, including immunocompetent and epithelial cells. Thus, it is reasonable to presume that this property may contribute to the pathogenesis of H. pylori-induced diseases. It may be involved on the one hand in immune response evasion and on the other hand in the suppression of epithelial repair mechanisms.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Reference45 articles.
1. Humoral and cellular immunity in HIV positive and HIV negative Helicobacter pylori infected patients;Benz J.;Int. J. Med. Microbiol. Virol. Parasitol. Infect. Dis.,1993
2. Helicobacter pylori and the pathogenesis of gastroduodenal inflammation;Blaser M. J.;J. Infect. Dis.,1990
3. Hypotheses on the pathogenesis and natural history of Helicobacter pylori-induced inflammation;Blaser M. J.;Gastroenterology,1992
4. Helicobacter pylori: microbiology of a `slow' bacterial infection;Blaser M. J.;Trends Microbiol.,1993
5. Campylobacter pylori and gastroduodenal disease;Buck G. E.;Clin. Microbiol. Rev.,1990
Cited by
62 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献