Fig. 2
SL/B immunization with a needle-free injector induces strong systemic antibody responses. a Syrijet, the needle-free injector used to deliver immunizations to the sublingual and buccal tissue. Sterile water cartridges were modified to contain immunogens. b Sublingual and buccal tissue of a rhesus macaque before and five minutes after 100 μl PBS injection via Syrijet. c Study design. Rhesus macaques (n = 15) were immunized twice with MVA-HIV (1 × 108 pfu) and boosted twice with recombinant trimeric gp120 (cycP-gp120) (100 μg) with the mucosal adjuvant dmLT. Animals were immunized via topical application to the sublingual and buccal (SL/B) tissue (n = 4), needle-free injection to the SL/B tissue (n = 5), or intradermally (with MVA-HIV) and subcutaneously (with cycP-gp120 + dmLT) (n = 6). MVA-HIV and cycP-gp120 doses were split between the buccal and sublingual tissue (SL/B) or the left and right thigh (ID/SC). 19 weeks following the second cycP-gp120 immunization, animals were challenged intra-rectally with low dose pathogenic SHIV-SF162P3 weekly for up to six weeks. Cartoons depict MVA-HIV and virus-like particles, cycP-gp120, and dmLT. d Kinetics of anti-gp120 (ADA) serum IgG in vaccine groups (geomean ± SD) and for individual animals (line, geomean ± SD) at the peak time point (wk 25) and pre-challenge time point (wk 45) (*, p < 0.05; Mann–Whitney test). Dotted lines denote week of indicated immunization. e Anti-dmLT serum IgG response in animals before (wk 25) and two weeks post (wk 45) immunization with cycP-gp120 + dmLT. d, e White circle, topical SL/B (n = 4); blue square, needle-free SL/B (n = 5); gray triangle, ID/SC (n = 6)
