Fig. 4.

Participation of cell-to-cell contact in Lactobacillus casei Shirota (LcS)-triggered enhancement of natural killer (NK) cell activity. CD14⁺ cell-enriched fraction (CD14⁺ Fr.) were cultured in 12F-well plate together with CD14⁺ Fr. in the presence of LcS at 1 µg/ml (without transwell) or left in 12F-well plates without making contact with CD14⁺ Fr. and LcS at 1 µg/ml given inside transwell (with transwell). After 6 days’ culture, NK cell activity of the surviving cells (a) and interleukin (IL)-12 concentration in the culture supernatants (b) were measured. Data are shown as mean ± s.e. of eight subjects. *P < 0·05; ***P < 0·001. (c) CD14^– Fr. and/or CD14⁺ Fr. were cultured in the conditions shown for 6 days, and NK cell activity of the surviving cells was measured. Data are mean ± s.e. of three subjects.