Neutralizing antibody responses against ID-VP02 can be detected after immunization. A, Ten-fold dilutions of serum taken from mice 28 days after immunization with the indicated doses of ID-VP02 (ID-VP02-GFP), VSV-G pseudotyped vector (VSV-G-GFP), or HBSS, were preincubated with a reporter vector (ID-VP02 encoding GFP) for 1 hour. This serum-vector mix was then used as test article in a GFP transduction assay utilizing 293T.huDC-SIGN target cells. The percentage of GFP+ cells was analyzed 2 days posttransduction. The results are presented as mean±SD of 3 mice per group. B, Groups of mice were first immunized with either 7.5×1010, 3.0×109, or 1.2×108 vector genomes of ID-VP02 encoding GFP, 7.5×1010 vector genomes of VSV-G pseudotyped lentivector encoding GFP, or HBSS. On day 28 postprimary immunization the animals were immunized with 3.0×109 of ID-VP02 encoding an alternative antigen cassette, LV1b. OVA257-specific CD8 T-cell response in the spleen was measured by intracellular cytokine staining (ICS) on day 12 after second immunization. *P≤0.05 between indicated groups (Mann-Whitney).