Folding pathway of AFM13. The fully functional TandAb antibody is formed by homodimerization of a single polypeptide in a head-to-tail fashion through noncovalent interactions of the immunoglobulin heavy (VH) and light (VL) variable chains of the constituting domains. The human anti-CD16A (FcγRIIIA) antibody domain (VHA/VLA) with specificity for the A isoform of FcγRIII on NK cells and macrophages was isolated from Affimed’s human antibody library. The murine anti-CD30 variable domain (VHB/VLB) was derived from hybridoma HRS-3.