VLP-display of flavivirus antigenic DIII domain. (A), Amino acid sequence of the CD16-RIgE cloning platform. The CD16-RIgE is a chimeric molecule composed of the extracellular domain of CD16, and transmembrane (TM) domain and cytoplasmic tail (CT) of the gamma chain of the human high affinity IgE receptor (FcϵRIg), abbreviated RIgE in the present study. Symbols for the different domains of the amino acid (aa) sequence are the following: italics, signal peptide (aa residues 1-22); standard capitals, ectodomain of CD16 (aa 23-209); underlined with dotted line, transmembrane domain (aa 210-231); underlined with solid line, cytoplasmic domain (aa 232-273); shaded residues, deletion (aa 23-206) of the CD16 ectodomain, replaced by the flavivirus envelope DIII domain. (B), Strategy of construction of the DIII-RIgE chimera (left), and of VLP-display (right), by co-expression with HIV-1 Pr55Gag in Sf9 cells doubly infected with baculovirus recombinants AcMPV-DIII-RIgE and AcMNPV-Pr55GagHIV.