Figure 4. Sublingual administration of an Ad5 vector expressing HIV-1 gp120 elicits robust antigen-specific serum IgG and IgA immune responses, while sublingual administration of a matched HSV-1 amplicon vector fails to do so.
An Ad5 vector encoding HIV-1 gp120 (1 × 108 VP), or a HSV amplicon vector (1 × 106 VP) encoding the same antigen was delivered IM or SL to female BALB/c mice; control animals were inoculated with PBS. A homologous boost was performed on day 14 and sera samples were collected on day 28. Sera from immunized mice were diluted 1:10, 1:100, and 1:1000 in PBS and incubated with ELISA plates coated with recombinant HIV-1 gp160 (MN strain, Protein Sciences). Peroxidase conjugated anti-mouse IgG (panel A) or anti-mouse IgA (panel B) were then added, as appropriate, and results were quantitated by measuring absorbance at 450 nm. The gray dotted line represents the background absorbance in this assay (this was set at 2 times the mean background absorbance in samples from PBS-treated control animals). Results represent mean values from 4 animals/group; bars denote the standard error of the mean. Data shown are representative of 2 experiments, performed with similar results. *: Denotes a statistically significant difference in the magnitude of the Env-specific serum IgG or IgA response in mice immunized with Ad:gp120 via the SL route versus the serum IgG or IgA response in mice immunized with HSV-1:Luc via the same route (p=0.0286; Mann-Whitney test).