AhpC interacts directly with CD81 and promotes internalization of fluorescein-tagged latex beads
(A and B) Protein coating of fluorescein-tagged latex beads with recombinant Mab Hsp16.7-His or AhpC-His. Labeling of Hsp16.7-His or AhpC-His proteins (red) at the surface of fluorescein tagged latex beads (green) was detected using mouse anti-His antibodies and Alexa Fluor 594 conjugated goat anti-mouse secondary antibodies.
(C) Ingestion of beads by THP-1 macrophages for 4 h is optimal when coated with AhpC. Data are mean values ±SD for three independent experiments (each time in octuplicate) (n = 240 fields). One-tailed Tukey’s test: ns, non-significant > 0.05, ∗∗∗∗p < 0.0001.
(D) Blocking CD81 with neutralizing antibodies drastically reduces the uptake of AhpC-coated beads. Data are mean values ±SD for four independent experiments (each time in quadruplicate) (n = 160 fields). One-tailed Tukey’s test: ns, non-significant > 0.05, ∗∗∗∗p < 0.0001.
(E) Representative fluorescent images showing either the efficiency of internalization and impact of neutralizing anti-CD81 antibodies on the internalization of AhpC-coupled beads by macrophages. CD43 (red), DAPI (blue) and fluorescent beads (green). White arrows indicate fluorescent beads inside macrophages.