Fig. 1: BLP strains expressing LAP from Listeria innocua (Lin) or Lm prevent Lm interaction in vitro.

a Schematics showing 99.4% amino acid sequence similarity of LAP from Lm and Lin (NCBI database). b Immunoblot showing cell wall expression and secretion of LAP in lap^─+lap^Lm and lap^─+lap^Lin strains. InlA and NamA: fractionation marker controls. Coomassie-stained gel (bottom panel) showing equal loading. c–e Restoration of adhesion (c, MOI 10, 1 h, n = 8 for all groups except for lap^─+lap^Lin, n = 7), invasion (d, MOI 10, 2 h, n = 6), and translocation (e, MOI 10, 2 h, n = 8) of the lap^─+lap^Lin strain in Caco-2 cells. f Immunoblot showing LAP expression in BLP strains in the cell wall and whole-cell fractions. g Immunofluorescence micrographs showing cell surface expression of LAP in BLP strains expressing LAP of Lm (arrows) or Lin (arrows). Lm (arrow) but not Lin shows the surface expression of LAP. Scale, 1 μm. h–j Increased adhesion of the BLP strains (MOE 10) (h, 1 h, n = 4, 4, 6, 6, 4, 4, for each group, respectively) but not invasion (i, 2 h, n = 3) and translocation (j, 2 h, n = 4) in Caco-2 cells. k–m Increased inhibition of Lm (MOI 50) adhesion (k, n = 6), invasion (l, n = 6), and translocation (m, n = 6) by the BLP strains (MOE 10, 24 h) in Caco-2 cells. n Increased adhesion of BLP (MOE 10, 1 h) strains in Hsp60^Vec cells (n = 3) and Hsp60⁺ cells (n = 4), but not in Hsp60^─ cells (n = 3-4) Caco-2 cells. o, p Increased inhibition of Lm adhesion (o, n = 3) and invasion (p, n = 3) by the BLP strains in Hsp60^Vec and Hsp60⁺, but not in Hsp60^─ Caco-2 cells. Panels c–e and h–p represent the mean ± SEM of n = independent cell culture wells from three independent experiments. The one-way (c–e and h–m) or two-way (n–p) ANOVA with Tukey’s multiple comparisons was used. For all analyses, ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05; ns no significance. Panels b and g are representative of three independent experiments. Source data are provided as a Source Data file.