Evaluation of both the His and V3 exposure capabilities on the capsid surfaces of four versions of hAd5-based V3 vectors. Whole virus ELISA was employed for this purpose. In this method, four versions of rescued vectors were coated in the wells of ELISA plates at various concentrations, starting from 4.5 × 109 VP/well, and serially diluted at 1:2, until an ending concentration of 4.0 × 106 VP/well. A) His exposure was evaluated separately in the vectors: Ad (diamond), Ad-HVR1-lgs-His6-V3 (square), Ad-HVR1-V3 (triangle), Ad-HVR1-long-V3 (dark circle) and Ad-HVR1-lgs-V3-His6-lgs (blank circle). B) V3 exposure was evaluated separately in the same five vectors, with the same order arrangement in Figure 2A. The values were expressed as the means from two replicates.