from what ive gathered from the abstract,t he glycosolation prevents a more robust immune response, less antibody titers, when they removed it they noticed the immune system recognizes the spike proteins more easily so a stronger immune response and more antibody produced, and a longer titre of antibodies.

first when they removed the “glycans” it revealed more of the protein of the virus, so the immune system recognizes different parts or more of it, so stronger and longer last immune response. the conserved parts is the parts of the proteins that dont mutate much so its easier to become immune to it, the sugars originally hid that part.