The heavy chain protein of HLA-peptide complexes (HLA/HBc(18-27) and HLA/CEA(694-702)) immobilized onto an ion exchange chromatography column and then the dilution-refolded HBc(18-27)-fused or CEA(694-702)-fused beta 2m protein was able to pass through the column. Using this method, HLA/peptide complexes were prepared within 30 h with a refolding yield of at least 20% (w/w) and purity of over 80% (w/w). This strategy refolds, concentrates, and purifies HLA/peptide complexes in a single integrated step and offers a potential tool to refold multiple-subunit proteins other than the major histocompatibility complex (MHC)/peptide complexes.