PPIB and infection: To study the interaction of DENV with FB and FH in the context of severe disease a model of DENV-infection of AG129 mice, lacking IFN-α, -β and -γ receptors, was utilized in (i) an acute setting where animals succumb after the decline in viremia [42, 43] and (ii) a model of more severe disease, reflecting ADE induced by pre-existing maternal antibody and leading to a fatal disease with onset closely after the peak in viremia [37, 44].