Effect of aglycosyl prM-reactive mAbs on DENV2 infection in AG129 mice. (A) WT or aglycosyl (N297Q) chimeric human Fc prM12 and prM13 mAbs were used in an in vitro ADE assay with the DENV2 D2S20 virus stock used to infect mice. After 24 h, infected cells were detected by intracellular staining with an E-specific antibody conjugated to Alexa Fluor 488. Error bars indicate the range of duplicate infections. (B) Groups of AG129 mice (n = 6 to 13, combined from two experiments) were administered 250 µg of the indicated WT or aglycosyl (N297Q) chimeric mAb intraperitoneally 1 d prior to retro-orbital inoculation with a lethal dose (1 × 104 FFU) of DENV2 D2S20. Survival was monitored. WNV-E16 is an isotype-matched control chimeric mAb. N297Q-modified mAbs demonstrated partial protection in comparison with their unmodified counterparts (P < 0.005 for prM12 vs. prM12 N297Q, and prM13 vs. prM13 N297Q comparisons, log-rank test). (C) Groups of AG129 mice (n = 11, combined from two experiments) were infected with a lethal dose (2 × 105 FFU) of DENV2 D2S20 via retro-orbital infection and 12 h later were administered 500 µg of aglycosyl human chimeric prM13 or an isotype control mAb. Survival was monitored. Therapeutic administration of prM13 N297Q was protective (P = 0.0005 for prM13 N297Q vs. isotype control, log-rank test). Images in panels B and C were created with BioRender.com.