1. A recombinant immune complex comprising: an immunoglobulin heavy chain; an immunoglobulin light chain; an epitope tag, wherein the immunoglobulin heavy chain binds the epitope tag; and a fragment of a virus protein, wherein the fragment of the virus protein is linked to the N-terminus of the immunoglobulin heavy chain, the epitope tag is linked to the C-terminus of the immunoglobulin heavy chain, and the epitope tag is from a different protein than the virus protein.