Extended Data Fig. 5: Binding of immunocomplexes to hamster splenocytes/FcgR and role of host effector function in SARS-CoV-2 challenge.
From: Lectins enhance SARS-CoV-2 infection and influence neutralizing antibodies
Alexa-488 fluorescent IC were titrated (0–200 nM range) and incubated with total naïve hamster splenocytes. Binding was revealed with a cytometer upon exclusion of dead/apoptotic cells and physical gating on bona fide monocyte population. a, fluorescent intensity associated to hamster cells of immune-complex (IC) made with either hamster (GH-S309, dark grey and GH-S309-N297A, blue) or human (Hu-S309, green) Fc antibodies. A single replicate of two is shown. b, relative Alexa-488 mean fluorescent intensity of the replicates measured on the entire monocyte population. Data are from a single representative experiment repeated three times with similar results. c–d, kinetics of binding of the same hamster and human ICs to hamster FcgRIV (panel C) and human FcgRIIIA (panel D) by Octet BLI analysis. e–g, Syrian hamsters (n = 6) were injected with the indicated amount (mg/kg) of hamster IgG2a S309 either wt or Fc silenced (S309-N297A). e, Quantification of viral RNA in the lung 4 days post infection. ** p = 0.0022 vs control. f, Quantification of replicating virus in the lung 4 days post infection. ** p = 0.0022 vs control g, Histopathological score in the lung 4 days post infection. ** p = 0.0022 vs C; * p = 0.0411 1.5 (N297A) vs C, p = 0.0130 4 (N297A) vs control. Control animals (white symbols) were injected with 4 mg/kg unrelated control isotype mAb. 2-tailed nonparametric Mann-Whitney t test (alpha threshold 0.05). Data are from a single experiment.
