The mortality rate due to COVID-19 in immunocompromised cases is considerably high. Monoclonal antibody (mAb) therapy is essential in managing SARS-CoV-2 infection, especially in immunocompromised cases. The mutation in the spike protein RBD region of the SARS-CoV-2 leads to the substitution of amino acids resulting in an altered ACE2 binding affinity. The mAbs must be tested in-vitro using standard neutralisation assays designed against emerging SARS-CoV-2 variants to estimate the mAb therapy efficacy. Based on already available data on the mAb efficacy for known SARS-CoV-2 variants, it is plausible to draw inferences for other closely related SARS-CoV-2 variants in circulation owing to the similar spike protein RBD amino acid sequence. In this article, we have attempted to analyse the data of mAb efficacy tested against SARS-CoV-2 variants and extrapolate on other emerging omicron sublineages like BA.2.75, BF.7 and BQ.1.
Mutations at positions 452 and 486 of the spike glycoprotein receptor binding domain (RBD) in the SARS-CoV-2 XBC.1 variant were analysed from the viewpoint of change in hydrophobicity and amino acid charge. A decrease in hydrophobicity due to mutations at positions 452 and 486 in the spike glycoprotein was observed, which might affect the infectivity of the XBC.1 variant. L452M and F486P improve the hACE2-RBD binding affinity, which might negatively impact the efficacy of vaccines against SARS-CoV-2, primarily based on spike glycoprotein. Notably, the mutation L452M in XBC.1 also indicates its probable zoonotic links.