Mycobacterium bovis BCG reverses deleterious effects of H. pylori components towards gastric barrier cells in vitro

Mycobacterium bovis (M. bovis) Bacillus Calmette-Guerin (BCG) strain used in immunotherapy of bladder cancer (onco-BCG) due to its acid tolerance can be a candidate for prevention or reversion of deleterious effects towards gastric cell barrier initiated by gastric pathogen Helicobacter pylori (Hp) with high resistance to commonly used antibiotics. Colonization of gastric mucosa by Hp promotes oxidative stress, apoptosis resulting in the gastric barrier damage. The aim of this study was to examine the ability of onco-BCG bacilli to control the Hp driven gastric damage using the model of Cavia porcellus primary gastric epithelial cells or fibroblasts in vitro. These cells were treated with Hp surface antigens (glycine acid extract-GE or lipopolysaccharide-LPS) alone or with oncoBCG bacilli and evaluated for cell apoptosis and proliferation in conjunction with the level of soluble lipid peroxidation marker (s4HNE). The cell migration was determined by "wound healing assay", while cytokine response of cells, including interleukin (IL)-33, IL-1 beta, IL-8 and tumor necrosis factor alpha (TNF-alpha), by the ELISA. The apoptosis of cells pulsed in vitro with Hp surface components present in GE or with LPS was reduced after exposure of cells to mycobacteria. Similarly, the cell regeneration which was diminished by Hp LPS has been improved in response to mycobacteria. This study reveals that vaccine mycobacteria may reduce gastric barrier damage induced by Hp infection.