Objective: To investigate the influence of the major histocompatibility complex (MHC) class I molecule HLA-B27 on (i) the invasion of Salmonella and Yersinia into human intestinal epithelial cells, (ii) the survival of intracellular Salmonella in these cells, and (iii) the production of certain inflammatory cytokines by the cells after Salmonella infection.
Methods: The human intestinal epithelial cell line Henle-407 was transfected with HLA-B27 DNA. These cells and HLA-B27-negative control cells were infected with Salmonella or Yersinia, and viable intracellular bacteria were determined as colony-forming units. Cytokine production was assayed with ELISA.
Results: Salmonella invaded HLA-B27-positive Henle cells in higher numbers than HLA-B27-negative control cells. However, HLA-B27 did not affect the invasion of Yersinia or the survival of the intracellular bacteria in these intestinal epithelial cells. Salmonella infection induced production of interleukin-8 (IL-8), IL-6 and monocyte chemotactic protein 1 (MCP-1) by Henle cells that was not affected by HLA-B27 in a specific way.
Conclusions: These findings suggest that HLA-B27 enhances the invasion of Salmonella into intestinal epithelial cells. The interaction between bacteria and intestinal epithelial cells plays an important role during the early phases of ReA. HLA-B27-linked modulation of Salmonella invasion may lead to an increased load of Salmonella in intestinal tissue and thus increased susceptibility to reactive arthritis.