[Bovine lactoferrin decreases the invasion of Salmonella enterica to HEp-2 cells].

OBJECTIVE: To assess the effect of bovine lactoferrin (bLf) on the invasion of Salmonella enterica ser. Typhimurium to HEp-2 cells.

MATERIALS AND METHODS: HEp-2 monolayers were infected with 106 colony forming unit (CFU) of bacteria in the absence and presence of 1 and 10 mg/mL of bLf (iron-saturated) and incubated 1.5 hours at 37°C. Two treatments were evaluated: pre- infection (HEp-2 cells were incubated with bLf one hour prior to infection with Salmonella) and post-infection (bLf was added 15 minutes after the infection). Invasiveness of Salmonella was determined throgh quantification of CFU recovered from inside the HEp-2 cells (after treatment with 100 μg/mL and 10 μg/mL of gentamicin and Triton X -100).

RESULTS: In the pre-infection treatment, we observed a decrease of 23% of Salmonella invasion when HEp-2 cells were pre incubated with 1 mg/mL of bLf (2.8x105 vs 2.1x105, p=0.04) and 50% when them were pre-incubated with 10 mg/mL of bLf (2.8x105 vs 1.4x105, p=0.04). In post-infection treatment, no changes were observed in the invasiveness of Salmonella.

CONCLUSION: The results indicated that bLf reduces the invasiveness of Salmonella enterica ser. Typhimurium to HEp-2 cells in the pre-infection treatment.