Method of producing a set of mhc molecules

A method of producing a set of MHC molecules, which set includes a plurality of subsets of MHC molecules, wherein the MHC molecules of each subset differ from MHC molecules of at least one other subset in at least one element selected from the group consisting of a peptide bound in the MHC binding groove, an MHC alpha chain protein and an MHC beta chain protein, said method comprising the steps of:

• a) providing the MHC molecules for each subset and loading said MHC molecules with said peptide by refolding in presence of said peptide or by peptide exchange, and
• b) purifying substantially in parallel the subsets of MHC molecules as obtained in step a) by a chromatographic method using a stepped gradient for elution.