Production of mAbs
Hybridoma Technology (Classical Method)
- Developed by Köhler and Milstein in 1975.
- Involves fusing an antibody-producing B cell (from a mouse immunized with the antigen) with a myeloma (cancer) cell to form a hybridoma.
- Hybridoma cells are immortal and produce large quantities of a single antibody.
Recombinant DNA Technology
Cloning of antibody genes into expression systems (e.g., CHO cells).
Allows for the production of humanized, fully human, or engineered antibodies.
Phage Display and Yeast Display
Antibody fragments (e.g., Fab, scFv) are displayed on the surface of phages or yeast cells.
Enables high-throughput screening for high-affinity binders.
Types of Monoclonal Antibodies
Humanized
Mostly human with only mouse CDRs
Chimeric
Mouse variable region+human constant region
Murine
Fully mouse antibodies; high immunogenicity
Fully Human
Entirely human sequences (via transgenic mice or phage display)
Bispecific mAbs
Bind two different antigens or epitopes
Applications of Monoclonal Antibodies
Therapeutics
Cancer: Target tumor-specific antigens (e.g., Trastuzumab for HER2+ breast cancer, Rituximab for CD20+ B-cell lymphoma).
Autoimmune Diseases: Inhibit inflammatory mediators (e.g., Adalimumab for TNF-α in rheumatoid arthritis).
Infectious Diseases: Neutralize viruses or bacteria (e.g., Palivizumab for RSV).
Allergy and Asthma: Block IgE or interleukins (e.g., Omalizumab).
Diagnostics
ELISA, Western Blot, Immunohistochemistry, Flow Cytometry: Detect specific proteins or biomarkers with high sensitivity.
Research Tools
Tag, isolate, or detect proteins and cells in molecular biology, cell signaling, and drug discovery studies.
High specificity:
Binds only to the intended target.
Reproducibility:
Same antibody can be consistently produced.
Modifiability:
Can be engineered for improved performance (e.g., affinity, stability, Fc function).
Costly production and storage.
Immunogenicity in some formats (especially murine).
Target resistance due to mutations (especially in cancer).