Method of screening antibodies with high antigen selectivity

A method of screening antibodies, the method comprising:

• contacting an antigen protein with a solution of calcium or calcium salt, wherein the antigen protein is a truncated version of a wild-type protein of interest;
• performing a negative selection on an antibody library, wherein the negative selection comprises contacting the library with a full-length version of the wild type protein of interest and removing any antibody bound to the full-length version of the wild type protein of interest from the antibody library;
• contacting the antibody library with the antigen protein in the presence of the calcium or calcium salt;
• and
• selecting one or more antibody or antibody fragments from the antibody library with the highest binding affinity to the antigen protein.