Figure 6
Bifidobacterium infantis attenuates Clostridium difficile -induced CCL20 secretion. Confluent HT-29 monolayers were pre-treated for 2 hr with 1 × 107 colony-forming units/ml (CFU/ml) live B. infantis or Lactobacillus salivarius prior to infection with 1 × 107 CFU/ml C. difficile bacteria or an equal volume of their cell-free supernatants, or 1 × 108 CFU/ml Mycobacterium paratuberculosis. CCL20 levels were measured 12 hr or 24 hr post-treatment as indicated. B. infantis, but not L. salivarius, restrained C. difficile- induced CCL20 secretion (*P < 0.05 compared with C. difficile- treated HT-29 cells). B. infantis did not limit M. paratuberculosis- induced CCL20 secretion. The data are expressed as per cent of pathogen-induced CCL20 secretion and represent the mean ± standard error (n = 6 independent experiments).