有点东施效颦的感觉

We vaccinated K18-hACE2 (mice) with mRNA-LNP (Pfizer/BioNTech BNT162b2) by IM injection (prime), followed 14 days later by IN administration of recombinant unadjuvanted spike protein (prime and spike (P&S)). Mice were euthanized at days 21 or 28 and assessed for mucosal humoral immunity (Fig. 1A).