Figure 3
MD39-liposomes elicit higher avidity trimer-focused antibody responses compared to soluble MD39 trimer immunization. Humoral responses in mice 3 weeks post-boost. Balb/c mice were immunized with 1 µg MD39 trimer and 0.2U ISCOMATRIX, and boosted at 6 weeks with the same formulations. Data shown contains pooled samples from 2 or 3 replicate experiments with each individual experiment having 3–5 animals/group. (A) Serum MD39–6xhis-specific titers (n = 8–12 animals/group). (B) Serum 6xhis tag-specific titers. (C) Serum MD39-specific titers determined by ELISA using non-6xhis tagged MD39 trimers to exclude histag-specific responses. (D) Serum V3-specific titers following immunization with 2 µg wild-type BG505 SOSIP trimers and 1 µg MPLA co-delivered either in soluble form or within non-covalent SOSIP liposomes (n = 4 animals/group). (E) Avidity of polyclonal antibodies from immunization with MD39 and ISCOMATRIX (from part A). (F) Serum MD39-6xhis-specific titers following immunization with MD39 on covalent liposomes at varying surface densities with ISCOMATRIX adjuvant (n = 5 animals/group). X-axis denotes average center-to-center trimer spacing on 150 nm liposomes. Dotted line in titer plots denotes limit of detection. *p < 0.05, Mann-Whitney test for titers and unpaired t test for avidity. Panel F was analyzed by a Kruskal-Wallis test.
