Such eRBCs were shown to exploit the natural method of RBC clearance to induce antigen-specific tolerance, both prophylactically and therapeutically, in a mouse model of multiple sclerosis.26 The second method genetically fused nanobodies (single domain camelid antibodies) targeting botulinum neurotoxin A to the RBC proteins glycophorin A (GPA) and Kell.25 When administered in an animal model, these eRBCs conferred sustained prophylactic protection against botulinum neurotoxin without provoking an immune response. The gene discussed is GYPA; the disease is multiple sclerosis.