AUTHOR=Frauenlob Tobias , Neuper Theresa , Mehinagic Muamera , Dang Hieu-Hoa , Boraschi Diana , Horejs-Hoeck Jutta 

TITLE=Helicobacter pylori Infection of Primary Human Monocytes Boosts Subsequent Immune Responses to LPS

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.847958

DOI=10.3389/fimmu.2022.847958

ISSN=1664-3224

ABSTRACT=<p>Infection with <italic>Helicobacter pylori (H. pylori)</italic> affects almost half of the world’s population and is a major cause of stomach cancer. Although immune cells react strongly to this gastric bacterium, <italic>H. pylori</italic> is still one of the rare pathogens that can evade elimination by the host and cause chronic inflammation. In the present study, we characterized the inflammatory response of primary human monocytes to repeated <italic>H. pylori</italic> infection and their responsiveness to an ensuing bacterial stimulus. We show that, although repeated stimulations with <italic>H. pylori</italic> do not result in an enhanced response, <italic>H. pylori</italic>-primed monocytes are hyper-responsive to an <italic>Escherichia coli</italic>-lipopolysaccharide (LPS) stimulation that takes place shortly after infection. This hyper-responsiveness to bacterial stimuli is observed upon infection with viable <italic>H. pylori</italic> only, while heat-killed <italic>H. pylori</italic> fails to boost both cytokine secretion and STAT activation in response to LPS. When the secondary challenge occurs several days after the primary infection with live bacteria, <italic>H. pylori-</italic>infected monocytes lose their hyper-responsiveness. The observation that <italic>H. pylori</italic> makes primary human monocytes more susceptible to subsequent/overlapping stimuli provides an important basis to better understand how <italic>H. pylori</italic> can maintain chronic inflammation and thus contribute to gastric cancer progression.</p>