Antigen Design: GAT Antigen Size
One of the advantages of the GAT approach is the ability to target the immune response to specific regions while still allowing for conformational epitopes (targeted specificity). The exact size of the antigen design for GAT depends on a number of different issues.
In general larger regions are preferred as these are more successful at generating high titer, multiple epitopes and conformational epitopes. However, in some circumstances there are restrictions preventing this (eg. loops flanked by two transmembrane domains).
We have investigated the influence of antigen size in GAT with a diverse panel of 10 target proteins. A set of 4 overlapping antigen designs were created (25aa, 50aa, 100aa, 150aa) and used to generate polyclonal antibodies in rabbits. A general trend is observed of higher titer with increasing antigen length.
The performance of the antibodies generated from the different length antigens were evaluated in a sandwich ELISA with full length protein. Different combinations of the antibodies were tested in sandwich ELISA. A general trend was observed with increased sensitivity in the ELISA with increased length of the antigen used to generate the antibody.