Zika virus (ZIKV) has spread in many countries or territories causing severe neurologic complications with potential fatal outcomes. The small primate common marmosets are susceptible to ZIKV, mimicking key features of human
infection. Here, a novel simian adenovirus type 23 vector-based
vaccine expressing ZIKV pre-membrane-envelope
proteins (Sad23L-prM-E) was produced in high infectious titer. Due to determination of immunogenicity in mice, a single-dose of 3×108 PFU Sad23L-prM-E
vaccine was intramuscularly inoculated to marmosets. This
vaccine raised antibody titers of 104.07 E-specific and 103.13
neutralizing antibody (NAb), as well as robust specific IFN-γ secreting T-cell response (1,219 SFCs/106 cells) to E
peptides. The vaccinated marmosets, upon challenge with a high dose of ZIKV (105 PFU) six weeks post prime immunization, reduced
viremia by more than 100 folds, and the low level of detectable
viral RNA (<103 copies/ml) in blood, saliva, urine and feces was promptly eliminated when the secondary NAb (titer >103.66) and T-cell response (>726 SFCs/106 PBMCs) were acquired 1-2 weeks post exposure to ZIKV, while non-vaccinated control marmosets developed long-term high titer of ZIKV (105.73 copies/ml) (P<0.05). No significant pathological lesions were observed in marmoset tissues. Sad23L-prM-E
vaccine was detectable in spleen, liver and PBMCs at least 4 months post challenge. In conclusion, a prime immunization with Sad23L-prM-E
vaccine was able to protect marmosets against
ZIKV infection when exposed to a high dose of ZIKV. This Sad23L-prM-E
vaccine is a promising
vaccine candidate for prevention of
ZIKV infection in humans.