It might be not to the point, but if you have any protocol which you can
measure your peptide, you can try the immuno-absorption assay.
When you mix the mouse serum with your peptide and protein-A or G or anti
mouse Ig coupled beads, if the serum has antibodies toward your peptide,
your peptide will be absorbed. So with measuring the remaining peptide
after absorption reaction, you can know the existence of antibodies in the
serum.
I don't remember exactly, but when I tried to detect anti peptide
antibodies, I used general immunoplate and coating buffer. For affinity
purification I used FMP activated Cellulofine gel. You can use this as
solid phase also.
