Immunology In The Clinic And Research Lab Flashcards
What are the two regions of a antibody?
Fc reigon - control reigon
Fab region - variable regions
how is a polyclonal antibody produced?
Set of B cells
Activated B cells
Antibody producing plasma cells
Antigen specific antibodies
How is a monoclonal antibody made?
Inject mouse with antigen
B cells harvested and fused with myeloma in polyethylene glycol
Select hybrid cells using HAT medium
- myeloma cells die as cannot make nucleotides
- B cells die as they have short life span
Grow hybrid cells in mass culture - clone cells - antibody’s produced and extracted
What happens to hybridomas after antibodies are produced?
Hybridomas can be stored indefinitely and grown to produce monoclonal antibodies
Antibody genes can be cloned from the hybridomas
What are anti-isotopic antibodies?
Polyclonal or monoclonal antibodies that bind to Fc regions of particular antibody classes
What are immunoassays?
Uses antibody-antigen interaction to measure the amount of antibody/antigen
What are the different labels in immunoassays?
Originally radioactive
Enzymes are used more commonly - detected by coloured product
Other alternatives are luminescent
What are the three types of solid phase. Immunoassays (ELISA)?
Direct
Indirect
Sandwich
Describe what occurs in the direct ELIZA test
- Antigen immobilised on solid support
- Test antibody solution covalently linked to enzyme added
- Enzyme substrate added, coloured product produced which can be measured by absorbance
What are the uses o a direct ELISA test?
Screen hybridoma supernatants
Detect exposure to infectious agent
Describe what occurs in the indirect Eliza test
- Antigen immobilised on solid support
- Primary antibody which binds to antigen is added
- Secondary antibody covalently attached to enzyme is subsequently added
- Secondary antibody bids to Fc region of primary antibody
- Enzyme substrate added, colour measured by absorbance
Describe what cures in the sandwich ELISA
- Antigens may be present in low concentration. Because antibodies have high affinity for antigen this technique the antigen
- Need 2 antigens reacting with different epitopes on the antigen
- One antibody mobilised on solid support
- Test antigen solution added, incubate and non-bound remove by washing
- Bound antigen detected by incubation with the other antibody which has been labelled, and non-bound removed by washing
How is a Elispot Assay conducted to measure cytokines secretion?
- Cytokine specific antibodies are bound to the surface of a plastic well
- Activated T cell are added to the well - these T cells are a mixture of different functions
- Cytokine secreted y some activated T cells is captured gy the bound antibody
- The captured cytokines is revealed by a second cytokines specific antibody, which is coupled to a enzyme, giving rise rise to a spot insoluble coloured precipitate
What is the use of SDS PAGE or western blotting?
- detect antigens and antibodies
- measure size of the protein analysed
- used to calculate protein concentration (intensity of a band comparison with a standard of a known concentration)
- May show if a protein has been degraded
Describe what occurs during purification
- Heterogenous population of lymphocytes is mixed with antibodies coupled to paramagnetic particles or beads and poured over iron wool mesh
- When a magnetic felid is applied the coupled cells stick to the iron wool, LABELLED cells are washed out
- When a magnetic field is applied the coupled cells which to the iron wool, UNLABELLED cells are washed out
- The magnetic felid is removed releasing he coupled cells