Fig. 1

GP1-reactive monoclonal antibodies from the memory B cells of a Candid #1 recipient. a ELISA of polyclonal IgG purified from human plasma samples with JUNV GP1-coated plates. “AHF high”, “AHF low”, and “No titer” are AHF survivors pre-determined to have 1:10,240, 1:40, and undetectable neutralizing antibody titers (PRNT₈₀) in their plasma, respectively. CR1: Candid #1 recipient. LUJV GP1 is a control. b HEK293T cells were infected with indicated pseudotypes after pre-incubation with polyclonal IgG (316 µg ml⁻¹). Entry levels (measured by FACS for GFP) are normalized to a no antibody (“No Ab”) control. c Representative density plot from a FACS experiment to isolate memory B cells that bind JUNV GP1 PE tetramers (sort 1, middle panel) or JUNV GP1 PE tetramers but not JUNV GP1_mut PerCP tetramers (excluded in a gating step that is not shown) (sort 2, rightmost most panel). The approximate location of the sorting gate is shown as a box, and the percentage of cells that fall within the gate is indicated. The leftmost panel is for a control donor using the sort 1 strategy. CD19 is a B-cell marker. d ELISA of the indicated monoclonal antibodies binding to immobilized JUNV GP1 or JUNV GP1_mut. LUJV GP1 is as a control. The calculated EC₅₀ values for antibody binding to WT JUNV GP1 are indicated in parentheses. e Sensorgrams for binding of Fabs to immobilized JUNV GP1 as measured by surface plasmon resonance. The recorded sensorgrams (one of duplicates) are shown. Calculated K_D values are in parentheses. f HEK293T cells were challenged with JUNV pseudotype after pre-incubation with monoclonal antibodies. IC₅₀ values are in parentheses. VSIV: vesicular stomatitis virus. For pseudotype neutralization studies, data are averaged from two independent experiments performed in duplicate. For ELISAs, the experiment was performed twice in duplicate and representative data are shown. Error bars indicate standard deviation (S.D.). For some data points, error bars are smaller than symbols