Figure 4.
Probiotic pretreatment down-regulates interleukin (IL)-8 secretion at baseline. Confluent HT-29 cells were treated with Bifidobacterium infantis or Lactobacillus salivarius at doses of 1 × 105, 1 × 106, or 1 × 107 colony-forming units (CFU)/ml, and IL-8 protein levels were measured after 6 hr. B. infantis and L. salivarius caused a dose-dependent inhibition of baseline IL-8 secretion by confluent HT-29 monolayers (*P < 0·05 compared with untreated monolayers). The data are expressed as pg/ml IL-8 and represent the mean ± standard error (n = 3 independent experiments).