SARS‐CoV‐2 nucleocapsid (N) protein has been proposed as a good vaccine target. N‐specific T cells were observed in SARS‐CoV‐2 N immunized mice and COVID‐19 convalescents. It is of importance to identify the T cell responses triggered by SARS‐CoV‐2 N protein. Intradermal immunization with SARS‐CoV N protein was demonstrated to elicit non‐protective T cell responses which may be avoided by intranasal vaccination. Therefore, we conducted intranasal vaccination of BALB/c mice with recombinant adenovirus type‐5 expressing SARS‐CoV‐2 N protein. Such procedure induced CD8 T cell responses in the lung. Meanwhile CD4 T cell responses were observed in the spleen, which was associated with robust antibody production. Our study further supports the notion that SARS‐CoV‐2 N protein can work as a target for vaccine development.

中文翻译：

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鼻内接种SARS-CoV-2核衣壳蛋白可诱导小鼠局部和全身T细胞反应

已提出将SARS‐CoV‐2核衣壳（N）蛋白作为良好的疫苗靶标。在SARS‐CoV‐2 N免疫小鼠和COVID‐19恢复期中观察到N特异性T细胞。识别由SARS-CoV-2 N蛋白触发的T细胞反应非常重要。已证明用SARS-CoV N蛋白进行皮内免疫可引起非保护性T细胞反应，鼻内疫苗接种可避免这种反应。因此，我们用表达SARS-CoV-2N蛋白的重组腺病毒5型对BALB / c小鼠进行了鼻内疫苗接种。这样的程序在肺中诱导了CD8 T细胞应答。同时，在脾脏中观察到CD4 T细胞应答，这与抗体产生旺盛有关。我们的研究进一步支持了SARS‐CoV‐2 N蛋白可以作为疫苗开发目标的观点。