Production Technology: Creating Hybridomas
To produce monoclonal antibodies on an industrial and medical scale, a special biotechnological procedure—hybridoma generation—is used. This process combines the best properties of the natural immune response and tumor cells.
The technological steps include:
- Cell fusion. Immune B lymphocytes (e.g., murine splenocytes) that produce the desired antibodies are harvested and fused with myeloma cells. Myeloma cells are tumor-derived and "immortal," but they lack the ability to produce their own antibodies.
- Use of a medium. The fusion process between these two cell types is triggered in the presence of a specific agent: polyethylene glycol (PEG).
- Hybridoma formation. This yields a hybrid cell. From the B lymphocyte, it inherits strict antigen specificity; from the myeloma cell, it inherits the unique ability to undergo endless division.
Thus, a single hybridoma can indefinitely produce homogeneous, highly specific antibodies.
Cultivation Methods
Following the successful generation of hybridoma cells, mass propagation is required to yield a sufficient quantity of antibodies. There are two main approaches to cultivation:
- In vitro — growing cells outside a living organism in specialized artificial cell cultures containing nutrient media.
- In vivo — injecting the hybridoma into the peritoneal cavity of a laboratory mouse. In this case, monoclonal antibodies accumulate in high concentrations in the animal's ascites fluid.
Antibodies obtained in this manner are actively used for clinical diagnostics, as well as for targeted therapy in oncology and severe autoimmune diseases.
Modified Monoclonal Antibodies
Since antibodies are initially derived using animal cells (murine lymphocytes), their direct administration to humans can trigger adverse immune reactions. To prevent this, biotechnology allows for the creation of modified variants widely used in endocrinology, the treatment of autoimmune diseases, and transplantation.
Chimeric Monoclonal Antibodies These represent a combination of murine and human protein components.
- Structure: The variable region (the Fab fragment), responsible for antigen specificity, is derived from mouse antibodies. The remaining constant portion of the molecule is replaced with a human IgG fragment.
- Application: Effective in treating autoimmune pathologies, such as rheumatoid arthritis.
Humanized Monoclonal Antibodies These drugs are structurally as close as possible to human immunoglobulins, containing the bare minimum of animal protein.
- Structure: Only small gene segments encoding the complementarity-determining regions (CDRs) derived from a rat are site-specifically "inserted" into human immunoglobulin genes.
- Application: Actively used in transplantation to prevent rejection of transplanted organs.
Prime examples of humanized antibodies are daclizumab and basiliximab—drugs that act as blockers of interleukin-2 (IL-2) receptors, thereby preventing the unwanted activation of T lymphocytes.