To confirm that the mechanism of enhancement involved entry of antibody-bound ZIKV particles through the K562 FcRII pathway, we pre-incubated K562 cells with a mouse anti-FcRII MAb prior to infection with ZIKV that had been pre-incubated with a highly enhancing dilution (1:50 000) of the ZIKV-neutralizing Singapore 1 serum. This evidence concerns the gene FCGR2A and infection.