Immunogenicity of glycan-deleted trimers.

(a) The immunogenicity regimen and respective immunogens for Groups 1, 2 and 3 are shown. In brief, rabbits were immunized at weeks 0, 4, 12 and 24. Test bleeds are indicated by the red arrows following each immunization. (b) Representative negative stain EM images of the liposomes coupled with the respective trimers. The white scale bar on the top wt trimer-liposomes image is equivalent to 100 nm. (c) Geometric mean IgG titers (GMT) as measured by His-capture ELISA to the wt autologous trimer immunogen following each inoculation. Immunizations are indicated by the vertical dashed gray lines. Six data points per time point per group were determined. Two independent ELISA experiments were performed and a representative experiment is shown.