Multiple variants of SARS-CoV-2 were identified. The KR variant B.1.427 L452R is one of the mutants found in Korea. Explain the meaning of these mutations.amino acid L (leucine) being replaced with R (arginine) at position 452.amino acid at position 452 has become LR (leucine and arginine)duplication of L (leucine) at position 452amino acid L (leucine) is deleted from position 452

The animal host for SARS-CoV-2 is the . After circulating among these animals in the wild for a long period of time, the virus accumulated mutations that allowed infection of humans.

Which of the following statements are true about SARS-CoV-2?SELECT ALL THAT APPLYThe virus attaches to host cells via its neuraminidase spike.The genome of SARS-CoV-2 undergoes mutations.SARS-CoV-2 is a naked virus.SARS-CoV-2 has an antisense RNA genome.The strain designation of SARS-CoV-2 is H1N1.SARS-CoV-2 causes Covid-19.

The viral vector vaccine developed by Johnson and Johnson uses a modified Blank______ carrying the genetic code for the Blank______ protein of SARS-CoV-2.Multiple choice question.coronavirus; spikeadenovirus; nucleocapsidcoronavirus; nucleocapsidadenovirus; spike

A SARS-CoV-2 variant that is more transmissible than others is one that can replicate Blank______ and has Blank______ attachment to epithelial cells in the upper respiratory tract of a new host.Multiple choice question.slowly; reducedquickly; reducedquickly; greaterslowly; greater

To assess the extent of immune escape of the SARS-CoV-2 Omicron variant, we first mapped its mutations on the RBD and compared these regions with the binding epitopes of some previously reported antibodies (Lu et al., 2021; Yu et al., 2020; Figure S1). According to the spatial overlapping of antibody epitopes and viral mutations, the RBD-targeting antibodies can be grouped into three types: those that bind to the RBM, those that bind the cryptic epitopes hidden or partially hidden inside the trimeric interface, and antibodies that bind to lateral surface epitopes outside the trimeric interface (Figure 1A). This classification was comparable to a study of a large panel of SARS-CoV-2 antibodies, which classified epitopes into RBM, inner face, and outer face (Hastie et al., 2021), corresponding to our groups of RBM, cryptic epitopes, and lateral surface epitopes. Evidently, more mutations were involved in the epitopes of apex RBM-binding antibodies than the other two clusters (Figure 1B). To confirm this finding, we measured the binding and neutralization titer of plasma collected from 7 vaccine recipients who received three doses of inactivated SARS-CoV-2 vaccine. The average median binding titer (ED50) of serum declined by 12.8-fold for Omicron RBD, while the neutralizing potency (average median neutralizing titer, ID50) decreased by 5.1-fold against Omicron pseudovirus (Figures 1C, S2A, and S2B). Interestingly, we found that some vaccinees had high binding and neutralizing antibody titers against the wild-type (WT) SARS-CoV-2 but relatively low neutralization titers against the Omicron variant. To understand the underlying mechanism, we performed epitope binning by saturating the RBM of the SARS-CoV-2 RBD with ACE2, and then loaded plasma to allow the binding of non-RBM antibodies (Figures 1D, S2C, and S2D). The Spearman’s rank correlation test was applied to measure the potential relationship between ID50 with RBM- or non-RBM-binding antibodies. This analysis revealed a high correlation between the binding of non-RBM a