A Novel Virus-Like Particle Based Vaccine Platform Displaying the Placental Malaria Antigen VAR2CSA
Fig 2
Verification of self-assembly and subsequent in vitro biotinylation of HPV16 Avi-L1 VLPs a Purification of HPV16 Avi-L1 VLPs (HI) VLPs was performed by ultracentrifugation (UC) on an iodixanol (OptiprepTM) density-gradient (27%/33%/39%).
Subsequent reduced SDS-PAGE analyses showed the presence of a 56kDa protein band (theoretical size of Avi-L1) in the high-density UC fractions (4–6) containing particulate material. b Transmission-electron microscopy (TEM) analysis of material representing UC fraction 4 post UC purification. To verify the integrity of the chimeric HPV16 Avi-L1 (HI) VLPs, an aliquot of diluted particles was placed on carbon-coated grids, negatively stained with 2% phosphotungstic acid (pH = 7.0) and examined by transmission electron microscopy (TEM) using a CM 100 BioTWIN at magnification x 36,000 (Å), scale bar 80 nm. c Western blot analysis of fraction 4 post UC purification. The blot demonstrates the presence of HPV16 Avi-L1 (56kDa) detected by Camvir-1 (lane one) and successful biotinylation of HPV16 Avi-L1 using Strep-HRP to detect biotin (lane two).