What can be done if the antigen is not soluble?
Usually it is possible to inject an insoluble antigen. If the particles can fit through an eighteen-gauge needle, it might work. It is recommended not to use detergents such as SDS to solubilise the antigen. The antigen / buffer mixture will be mixed to make an emulsion with the adjuvant to ensure a homogeneous preparation. You could also run multiple lanes of a gel and cut out the bands of interest and send us gel-imbedded protein as sample.