A priori, the establishment of recombinant SLA molecules is complicated by the lack of validated reagents. Any failure could therefore be caused either by real technical problems in generating SLA molecules, or merely by a lack of information about strong peptide binders to the SLA in question. To reduce this uncertainty, we decided to migrate from human to pig MHC-I in a step-wise manner and generate an intermediary chimeric MHC-I molecule composed of a well-known human peptide-binding platform attached to a SLA stalk, which might allow us to assess whether we could generate a functional SLA stalk consisting of SLA-1*0401 α 3 HC and pig β 2 m. To this end, we used the α 1 α 2 domains of the HLA-A*11:01 molecule, which we expected should be able to bind a known highaffinity HLA-A*11:01-binding peptide (KVFPYALINK). This peptide could be 125 I radiolabeled and used in a very robust peptide-binding assay testing whether the human stalk could be replaced with the corresponding SLA stalk. Once that had been successfully established, the entire SLA-1*0401 molecule would be constructed and tested.