Dose-response effect of 5000 g·mol⁻¹ fraction obtained after Amicon Ultra15 filtration from milk fermented by E. faecalis TH563 (a) or L. delb. bulgaricus LA2 (b) by MTT proliferation test, in the presence (■) or in the absence (●) of the mitogen concanavalin A (conA). The data were expressed as the percentage of the optical density observed in conA-treated BPBL cultured without fermented milk but in the presence of conA (positive control). Results are presented as means ± SEM of nine independent experiments for each strain. Asterisks indicate means significantly different from the positive control (*P < 0.001; **P < 0.01; Dunnett t-test).