monoclonal antibodies
Summary
Monoclonal antibodies (mAbs) are laboratory-produced antibodies derived from a single B-cell clone, engineered to bind one specific epitope with high specificity. They are widely used therapeutically (e.g., cancer, autoimmune disease, infection) and diagnostically. Nomenclature suffixes indicate their origin (e.g., -ximab = chimeric, -zumab = humanized, -umab = fully human).
Detail
Monoclonal antibodies are produced using hybridoma technology (originally developed by Köhler and Milstein), where antibody-producing B cells are fused with immortal myeloma cells to create hybridomas that continuously produce identical antibodies against a single antigenic epitope. Modern production often uses recombinant DNA technology to create chimeric, humanized, or fully human antibodies to reduce immunogenicity (human anti-mouse antibody reactions).
Naming convention (high-yield for boards): - '-omab' = murine (100% mouse) - '-ximab' = chimeric (mouse variable region + human constant region) - '-zumab' = humanized (mostly human, small mouse CDR regions) - '-umab' = fully human
Mechanisms of action include: neutralizing soluble ligands (e.g., bevacizumab blocks VEGF), blocking cell surface receptors (e.g., trastuzumab blocks HER2), inducing antibody-dependent cellular cytotoxicity (ADCC), complement-mediated cytotoxicity, and immune checkpoint inhibition (e.g., nivolumab/pembrolizumab block PD-1; ipilimumab blocks CTLA-4).
Clinical applications are extensive: - Oncology: trastuzumab (HER2+ breast cancer), rituximab (CD20, B-cell lymphomas), bevacizumab (VEGF, various cancers), cetuximab (EGFR, colorectal cancer) - Autoimmune/inflammatory: infliximab/adalimumab (TNF-alpha inhibitors for RA, IBD, psoriasis), natalizumab (α4-integrin, multiple sclerosis) - Infectious disease: palivizumab (RSV prophylaxis) - Hematology: eculizumab (complement C5, PNH) - Allergy/Asthma: omalizumab (anti-IgE)
Key adverse effects to know: infusion reactions, increased infection risk (especially with TNF inhibitors - reactivation of latent TB, requiring PPD/IGRA screening before starting), progressive multifocal leukoencephalopathy (PML) with natalizumab (JC virus reactivation), and cardiotoxicity with trastuzumab.
This is a high-yield pharmacology topic for Step 1/2, often tested via mechanism-target-drug matching and recognizing suffix patterns to predict drug class and origin.
Sources
- First Aid for the USMLE Step 1
- Katzung's Basic and Clinical Pharmacology
- Kuby Immunology
- UpToDate
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.