Strategies to use the glycosylation of SARS-CoV-2 in vaccination
Covid-19 utilizes its glycosylated spike protein (S protein) to interact with the human angiotensin-converting enzyme 2 (Hace2) and achieve membrane fusion. The revealed and potential glycan profile might be interesting as the next step for antibody design.
How many glycosylation sites and where are they? The spike protein (S protein) has around 69-87 N-linked glycosylation sites in each trimeric spike. Yasunori et al. have worked out the glycan shield of SARS-COV-2 using mass spectrometry data and cryo-EM analysis.
What is the function of the sugars? The glycans on the S protein surface were supposed to have an effect in preventing the virus from the immune system. It was found that the receptor binding sites on S protein are shielded by proximal N165, N234, N343 glycosylation sites, which might provide protection for their binding area.
How to screen out the lectins which specifically interact with the sugars? Use a phage display to screen out the lectin which could bind to the sugar type in S protein.
The potential of the lectins in vaccine or detection. Fuse the specific lectin together with antibodies might be a potential method for developing vaccines.
Potential risk: serious off-target effect. The unique expressed glycan on the S-protein surface is critical for such a strategy.