Fig. 4 | Nature Communications

Fig. 4

From: Variant surface glycoprotein density defines an immune evasion threshold for African trypanosomes undergoing antigenic variation

Fig. 4

The effect of VSG density on IgM binding ability. a VSG2-specific Ab binding to wild-type (WT) and dual expressor (DE) clones. Monoclonal anti-VSG2 IgG Ab was used as a control to demonstrate the presence of surface VSG2 in all DE clones (left). Binding ability of two polyclonal IgM antisera is shown on the right. Data are representative of three replications of this experiment. b, c A model detailing a proposed mechanism for the observed IgM binding threshold. b The binding footprint of IgM. Modeling the VSG coat (bottom) as a hexagonal array of VSG homodimers with a spacing of ~5.8 nm, an IgM molecule (top) with a diameter of 40 nm could contact a maximum of 61 homodimers (122 VSGs) at a single time. c The average number of initial VSGs within a given IgM binding footprint at varying stages of coat replacement

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