Fig. 5: Intravenous phage efficacies are differentially tempered by antibody-mediated neutralization.
From: Ecological partitioning enables phage–antibiotic cooperation in a human Pseudomonas infection
a Stacked bar plots showing the relative abundance of Pseudomonas-infecting and other viral taxa in sputum before, during, and after co-therapy. Therapeutic phages P1A (Pakpunavirus; blue) and PYO2 (Litunavirus; red) are highlighted alongside endogenous airway phage genera (Pbunavirus, Phikzvirus, Phikmvvirus, and others). Viral taxa comprising <1% of total reads are grouped as “other” (black). b, c Temporal dynamics of therapeutic phages in sputum. b Host-normalized absolute abundance of P1A and PYO2. P1A abundance increased sharply by day 3 to ~141 virions per human cell, consistent with in situ replication. c Phage-to-bacterium ratio (multiplicity of infection, MOI) in sputum. Despite a ~10-fold reduction in P1A reads after day 3, concurrent bacterial decline maintained a mean MOI near 0.8 throughout co-therapy. d, e Serum evidence of phage-specific immune responses. d In vitro phage neutralization, measured as efficiency of plating (EOP). Neutralization increased over the course of treatment, resulting in near-complete loss of both phages by two weeks. Data are presented as mean ± SD (n = 4). One-way ANOVA with Dunnett’s multiple comparisons to day 0. Asterisks denote adjusted p values (*<0.05; ** <0.01). e Anti-phage IgM responses measured by ELISA. IgM against PYO2 rose rapidly and remained elevated, consistent with pre-existing cross-reactive immunity, whereas anti-P1A IgM appeared later and increased gradually. Data are presented as mean ± SD (n = 3). One-way ANOVA with Dunnett multiple comparisons to day 0. Asterisks denote adjusted p values (*< 0.05; ** <0.01; *** <0.001). f, g Hematologic indicators of systemic inflammation during treatment. f White blood cell (WBC) counts and g platelet counts measured from whole blood. Dashed lines denote baseline means (WBC = 5,375 ± 1,250 cells µL−1; platelets = 2.18 × 105 ± 1.02 × 104 cells µL−1). Mild transient increases correspond to the onset of anti-phage IgM induction.
