Figure 3. Serum PEG Antibody Responses in HVTN133 Participants.

We measured sera IgG antibodies that bound to PEG using a commercially available kit in samples collected from vaccine (A) and placebo (B) recipients over time. Arrows indicate the immunization timepoints. Shown are averaged normalized optical densities (OD) for binding data from duplicate assays. Normalized OD = threshold set to >1 (after being normalized to 1U/ml kit calibrator); Human Anti -PEG IgG ELISA Kit (Alpha Diagnostics International, San Antonio, Texas). Participant 133–33 experienced anaphylaxis after the third vaccination and participant 133–39 experienced an injection site eruption also after the third vaccination.