Lecture 8 Antibodies Flashcards
Describe the structure of an antibody.
- Antibodies consist of two identical heavy chains and two identical light chains.
- They have a Fab region at the top end of the Y portion, containing one constant and one variable domain from each chain.
- The antigen-binding site is located in the CDRs,
- the Fc domain, found at the stem of the Y, is composed of constant regions from the heavy chains.
What is the function of the Fc domain of an antibody?
- Fc domain of an antibody binds to receptors and complement proteins
- playing a role in triggering immune responses and interactions with other immune cells.
How is antibody specificity generated?
- Antibody specificity is generated through the complementarity determining regions (CDRs), which are hypervariable loops crucial for the diversity of antigen specificities.
Define VDJ recombination in the context of antibodies.
- VDJ recombination is the process by which the variable regions of antibodies are generated through the rearrangement of gene segments (V, D, and J) in B cells, leading to the diversity of antigen recognition.
What are the functions of antibodies in the immune system?
- Antibodies play a vital role in preventing pathogens from entering or damaging cells,
- stimulating the removal of pathogens by immune cells
- triggering the destruction of pathogens through immune responses like the complement pathways.
Describe the difference between polyclonal and monoclonal antibodies.
- Polyclonal antibodies are a mixture of antibodies from multiple B cell lineages,
- monoclonal antibodies are derived from a single B cell lineage, providing more uniform and specific antigen recognition.
How are polyclonal antibodies typically produced?
- an antigen is injected into an animal like a rabbit,
- which activates B cells.
- The plasma B cells then produce a mixture of antibodies,
- and antiserum containing polyclonal antibodies is obtained from the animal.
Describe the process of creating monoclonal antibodies.
- Mice are immunized with a specific antigen, leading to the production of antibodies by murine spleen cells.
- These cells are fused with myeloma cells to form hybridomas, which produce the desired antibodies collected from the cell supernatant.
What are some hurdles to the development of monoclonal antibody therapeutics?
- Rapid clearance,
- intolerance problems,
- the immune system recognizing the therapeutic antibody as foreign, leading to neutralizing antibodies being produced and removing the therapeutic antibody from the blood.
How are transgenic mice used to produce fully human monoclonal antibodies?
By transferring human Ig genes to mice, immunizing them, and generating human monoclonal antibodies from the transgenic mice.
Define stability issues associated with monoclonal antibodies.
Stability issues include oxidation, isomerization, deamidation, aggregation, denaturation, and fragmentation due to their proteinous nature.
Describe the impact of formulation and stability on monoclonal antibodies and the factors the affect it
Formulation and stability impact mAB structure, activity, and immunogenicity. Factors like temperature, pH, humidity, and stress conditions can affect their stability.
How does the choice of excipient affect monoclonal antibody formulations?
The choice of excipient is crucial in monoclonal antibody formulations as it can impact stability, immunogenicity, and viscosity, affecting the overall efficacy of the antibody.
Explain the differences in administration routes for monoclonal antibodies.
Monoclonal antibodies can be administered intravenously for rapid circulation, or subcutaneously/intramuscularly for slower absorption. Subcutaneous administration is preferred by patients for self-administration, increasing compliance and reducing healthcare burden.
Describe the impact of viscosity on the administration of monoclonal antibodies.
High viscosity of extracellular matrix can impair fluid flow during administration, affecting the distribution and effectiveness of monoclonal antibodies in the body.
