2.5. Adhesion assay
An in vitro adhesion assay was performed using the method
described by Sugimura et al. [8]. Caco-2 cells were grown in Dulbecco's
modified Eagle's medium (DMEM; HyClone, Laboratories
Inc., Logan, UT, USA) supplemented with 10% heat-inactivated fetal
bovine serum (FBS; HyClone), L-glutamine (2 mmol/L), penicillin
(100 U/mL), and streptomycin (100 mg/mL) in an incubator with
95% (v/v) humidified air and 5% (v/v) CO2 at 37 C. The Caco-2 cells
(1 105 cells/mL) were seeded into 24-well tissue culture plates
and fully differentiated for 16 days (post-confluence) by changing
the culture medium every 2 days. The cells werewashed twice with
PBS (pH 7.4) to remove the excess unattached cells. One milliliter of
each lactobacilli suspension (1 109 CFU/mL in antibiotic-free
DMEM) or DMEM solution (as control) was added into each well