3.2.2: Uses of monoclonal antibodies
Not started yet — this one needs some love.
Pregnancy tests: detect hCG hormone in urine using antibodies specific to hCG.
Laboratory diagnosis: detect or measure hormone/chemical levels in blood; detect specific pathogens using antibody specificity.
Research: locate or identify specific molecules in cells/tissues by attaching fluorescent dyes (or radioactive markers) to the monoclonal antibody.
Cancer treatment:
a monoclonal antibody is bound to a radioactive substance, toxic drug or growth-inhibiting chemical
it binds specifically to antigens on cancer cells → the substance is delivered to cancer cells only
minimal damage to healthy cells, because the antibody is specific
How they work: a monoclonal antibody's shape is complementary to the antigen's shape → very precise, specific binding → only targets cells/pathogens with the matching antigen.
Advantages: highly specific to one antigen; can target individual cell types without harming others.
Disadvantages: can cause unexpected side effects; expensive; not as widely successful as originally hoped.
Common exam mistakes
Complementary shape binding: the monoclonal antibody's binding site has a shape complementary to the antigen's shape — like a lock and key. Just saying 'specific' or 'binds to antigen' without explaining the shape matching is insufficient at higher tier.
Antibody does NOT change shape or destroy the antigen — the antibody binds to the antigen through shape complementarity; the antigen's shape does NOT change.
Monoclonal antibodies are administered as purified antibodies only — patients are NEVER given hybridoma cells (hybridomas remain in the laboratory culture).
In cancer treatment, the antibody carries/delivers a toxic substance to cancer cells — the antibody's role is to transport/target, not to directly kill. The toxic payload does the killing.
Do NOT confuse: antigen (target molecule on pathogen/cancer cell), antibody (protein that binds to antigen), hybridoma (cell that produces antibody).
The specificity comes from shape complementarity — if you only say 'it's specific' you have not explained HOW it's specific.