Figure 3.

Antibody responses at different timepoints after vaccine administration

(A) Neutralising antibody magnitude–breadth curves are shown against a panel of six Env-pseudotyped tier 1 HIV-1 isolates (BaL.26, MN.3, SF162.LS, MW965.26, NP03.13, and TH023.6) 2 weeks after the month 1 (month 1·5), month 3 (month 3·5), and month 6 (month 6·5) vaccinations and 6 months after the month 6 vaccination (month 12). The AUC, interpretable as the geometric mean ID₅₀ titre across viruses, was used to compare groups. Individual participants are dashed lines and treatment group averages are solid lines. (B) IgG binding antibody responses and magnitudes among positive responders were measured by binding antibody multiplex assays 2 weeks after the month 1 (month 1·5), month 3 (month 3·5), and month 6 (month 6·5) vaccinations, and the durability of the antibody response was measured 6 months (month 12), 9 months (month 15), and 12 months (month 18) after the month 6 vaccination. IgG binding antibodies were measured against three vaccine-matched antigens (aggregate vaccine-matched responses) and three V1/V2 antigens. Responses to aggregate vaccine-matched antigens were judged positive if a positive response was seen to any of the vaccine-matched antigens. Errors bars show 95% CIs (upper panels) or IQRs (lower panels). (C) IgG binding magnitude AUC values are shown against aggregate vaccine-matched antigens and three V1/V2 antigens. Net MFI values are shown, and net MFI values less than 100 were truncated for MFI calculation. The AUC from months 0–18 (month 0 vaccination to 12 months after the month 6 vaccination) was calculated using the trapezoidal rule for every fully vaccinated participant. Boxplots represent the distribution of positive responders with net MFI values greater than 100. T1=two doses of NYVAC vector followed by two doses of NYVAC vector and gp120 Env protein. T2=four doses of NYVAC vector and gp120 Env protein. T3=two doses of DNA vector followed by two doses of NYVAC vector and gp120 Env protein. T4=two doses of DNA vector and gp120 Env protein followed by two doses of NYVAC vector and gp120 Env protein. C=placebo groups (C1–C4), comprising matched injections. Env=envelope. AUC=area under the curve. ID₅₀=number of virus particles needed to produce infection in 50% of people. MFI=mean fluorescence intensity.