Fig. 3.

Characterization of baculovirus-expressed ZIKV VLPs. A Lysates of vAc-prME-infected Sf9 cells were layered onto 10%–60% sucrose gradients and subjected to centrifugation. Twelve fractions were taken from top to bottom. B Western blot analysis of purified sucrose gradient fractions using the indicated antibodies. C Electron micrographs of negative staining and immunogold labeling of VLPs and ZIKV. C–a Negative staining of purified ZIKV VLPs from the E and prM antigen-enriched fractions from the sucrose gradient; IEM of VLPs using anti-prM C–b, anti-E, C–c polyclonal antibodies and rabbit pre-immune serum, C–d as primary antibodies; C–e Negative staining of purified ZIKV; IEM of ZIKV using anti-prM C–f, anti-E, C–g polyclonal antibodies and rabbit pre-immune serum, C–h as primary antibodies; Scale bars = 50 nm.