Method of producing an immunoligand/payload conjugate

A method of producing an immunoligand/payload conjugate, the method comprising

• a) providing an immunoligand selected from the group consisting of:
• (i) an antibody,
• (ii) an antibody-based binding protein being a protein containing at least one antibody-derived VH, VL, or CH immunoglobulin domain,
• (iii) an antibody fragment binding to a receptor, antigen, growth factor, cytokine and/or hormone, and/or
• (iv) an antibody mimetic selected from the group consisting of DARPins, C-type lectins, A-domain proteins of S. aureus, transferrins, lipocalins, 10th type III domains of fibronectin, Kunitz domain protease inhibitors, affilins, gamma crystallin derived binders, cysteine knots or knottins, thioredoxin A scaffold based binders, nucleic acid aptamers, artificial antibodies produced by molecular imprinting of polymers, and stradobodies, and
• b) enzymatically conjugating at least one payload to the immunoligand by a sequence-specific sortase or a catalytic domain thereof, wherein the payload is a toxin having a molecular weight not exceeding 2,500 Dalton,
• wherein either
• the immunoligand comprises a sortase recognition motif and the toxin is modified with a Glyn-modification, wherein n>1, or
• the toxin comprises a sortase recognition motif and the immunoligand is modified with a Glyn-modification, wherein n>1,
• thereby producing the immunoligand/payload conjugate.