Fig. 2: Immunogenicity of MPV/S-2P in the airways.

Immunogenicity in the upper airways (UA) and lower airways (LA) was evaluated from nasal washes (NW) (A–C) and bronchoalveolar lavages (BAL) (D–G), collected at the indicated day pi. Spike (S)-specific and receptor binding domain (RBD)-specific IgG (A, D) and IgA (B, E) was measured using ELISA and dissociation-enhanced lanthanide fluorescent (DELFIA) assays, respectively (limit of detection: 1.6 log₁₀, dotted line). Dimeric anti-S IgA in the UA and LA was also evaluated by DELFIA assay (C, F; limit of detection is 1.0 log₁₀, dotted line). G BAL samples were analyzed for their ability to block binding of tagged, soluble ACE2 to purified S protein from the vaccine-matched SARS-CoV-2 S protein (Wuhan strain) or variants of concern. ACE2 binding inhibition is expressed as % inhibition relative to a no-sample control (see also Fig. S2A). A–G Medians (lines), min and max values (whiskers), 25th to 75th quartile (boxes), and individual values are shown for MPV primed (n = 4), MPV/S-2P primed (n = 8) and boosted (n = 4) macaques; two-way ANOVA with Sidak post-test; exact p values are indicated for levels of significance p < 0.05. Source data are provided in the Source Data file.