I guess I'm just skeptical that anyone can be truly sure of which exposed epitopes are conserved (I haven't seen data on this residue or drug, these are just my

I guess I'm just skeptical that anyone can be truly sure of which exposed epitopes are conserved (I haven't seen data on this residue or drug, these are just my thoughts). Given that we're talking about a three dimensional structure, you really need a number of conserved residues in physical proximity to have an inescapable monoclonal antibody. It seems quite possible that there aren't any targets like this and that only a polyclonal immune response, or maybe a cocktail of monoclonals, can be effective in the long-term.