Abstract
We previously reported that a single immunization with an adenovirus serotype 26 (Ad26)-vector-based vaccine expressing an optimized SARS-CoV-2 spike (Ad26.COV2.S) protected rhesus macaques against SARS-CoV-2 challenge. To evaluate reduced doses of Ad26.COV2.S, 30 rhesus macaques were immunized once with 1 × 10 11 , 5 × 10 10 , 1.125 × 10 10 , or 2 × 10 9 viral particles (vp) Ad26.COV2.S or sham and were challenged with SARS-CoV-2. Vaccine doses as low as 2 × 10 9 vp provided robust protection in bronchoalveolar lavage, whereas doses of 1.125 × 10 10 vp were required for protection in nasal swabs. Activated memory B cells and binding or neutralizing antibody titers following vaccination correlated with protective efficacy. At suboptimal vaccine doses, viral breakthrough was observed but did not show enhancement of disease. These data demonstrate that a single immunization with relatively low dose of Ad26.COV2.S effectively protected against SARS-CoV-2 challenge in rhesus macaques, although a higher vaccine dose may be required for protection in the upper respiratory tract.
Keywords: Ad26.COV2.S; COVID-19; SARS-CoV-2; humoral immunity; immunology; memory B cells; non-human primates; protection; vaccination.
【저자키워드】 COVID-19, immunology, SARS-CoV-2, vaccination, protection, memory B cells, Humoral immunity, Ad26.COV2.S, non-human primates, 【초록키워드】 Efficacy, Vaccine, vaccination, vaccine doses, immunization, Adenovirus, vaccine dose, low dose, disease, upper respiratory tract, memory B cell, Neutralizing antibody titer, Protective, binding, SARS-CoV-2 spike, rhesus macaques, rhesus macaque, Bronchoalveolar lavage, dose, humoral, serotype, nasal swabs, viral particle, immunized, memory B, robust, evaluate, reported, required, provided, reduced, correlated, expressing, 【제목키워드】 rhesus macaque,