(A) Fab 1H10 enhanced attachment of the fully immDENV to anionic liposomes which composition mimic that of the endosome. Presence of virus was detected in different fractions of the sucrose gradient in a virus-liposome co-floatation assay by anti-E antibody. At all pH 8.0 conditions, with or without liposome and Fab, immDENV remained in the middle fractions where the viruses were loaded initially onto the gradient. At pH 5.0, immDENV co-floated with the liposomes in the top 4 fractions indicating some interactions with the liposomes. When Fab 1H10 was added to the virus-liposome mixture at pH 5.0, all immDENV was detected only in the topmost fraction indicating enhanced interaction with liposomes. The assay was repeated three times and showed consistent results.
(B) IgG 1H10 enhanced infection of immDENV3 in THP-1 cells at equal or higher than molar ratio of 1 antibody per viral prM molecule.
See also
Figure S2.