If you have or can deduct a structure (pdb file), you could try to dock peptide sequences in silico. Otherwise (and to verify the theoretical results), you need to do epitope mapping, i.e. to spot short synthetic peptides on a membrane or use them to block the antibody in a ELISA or WB, and test if the antibody is recognizing them. There are also approaches by phage display (IIRC, there is a kit from NEB).

Thank you Wolfgang

I designed this immunogen, in silico. But the sequence is different from the reported in the literature. Is there any way to be more sure of the selected sequence before peptide synthesis?