Immunological Therapies Quiz

See Types. Option D is correct. Under the historical source-based naming system the last letters of an antibody drug name hint at how much of its sequence is human. Humanised antibodies (ending in -zumab) are engineered so that the sequence is predominantly human, and the non-human part is limited to the complementarity-determining regions, the loops at the tips of the antibody that physically bind the antigen. Keeping some mouse loops preserves binding, and a few extra mouse residues may be retained for the same reason. Because most of the molecule is human, humanised antibodies are less likely to provoke an immune reaction than mouse or chimeric antibodies. They can still cause some reactions, because the antigen-binding loops remain partly foreign. The system has largely been replaced: WHO now names new antibodies using structural endings such as -tug, -bart, -ment and -mig, so the older endings are still useful for established medicines but are not a universal rule for new drugs. Memory aid: the more human the antibody, the further it moves from the mouse:

• -omab: murine, entirely mouse
• -ximab: chimeric, a cross between species (non-human variable regions with human constant regions)
• -zumab: humanised, mostly human with mouse binding loops
• -umab: fully human

• Ending: -zumab means humanised
• Make-up: mostly human, with mouse sequence limited to the antigen-binding loops
• Immunogenicity: lower than mouse or chimeric antibodies, but not zero