Infection with Zika virus is asymptomatic in most people; however, devastating disease can occur in fetuses developing in infected mothers. In Cell, Robbiani et al. identify various neutralizing antibodies to Zika obtained from two independent cohorts in Brazil and Mexico. A large proportion of those antibodies are derived from somatically mutated B cell clones bearing VH3-23–Vκ1-5 immunoglobulin chains. Structural analysis reveals interaction between both immunoglobulin chains and two adjacent amino acid residues, Glu393 and Lys394, found in domain III of the Zika envelope protein. Similar antibody recognition occurs with envelope protein of dengue virus serotype 1 but not with envelope proteins of other related flaviviruses. The authors show that neutralizing cross-reactivity occurs in people exposed to dengue virus serotype 1 before infection with Zika virus, which might explain the higher frequency of neutralizing antibodies identified in their cohorts.

Cell (4 May 2017) doi:10.1016/j.cell.2017.04.024