Immunodiagnostics + Vaccines - TOKA Flashcards
What are polyclonal Ab?
Many different clones of B cells that are specific for several epitopes of an Ag
*** found in serum, used for Anti-serum
What are monoclonal Ab?
Ab specific for 1 epitope
products of a single B cell clone
** can not be produced in animals
How are monoclonal Ab produced?
- Injecting an Ag over 3 boosters
- Collecting spleen cells from the animal bc germinal centers with differentiated B cells
- Fuse spleen cells and myeloma cells
- Makes a hybridoma - B cell + tumor cell
** B cell contributes Ab, Tumor cell allows endless replication !!
- Dilute hybridomas so there is only 1 cell, then culture to amplify cell
What does an indirect ELISA detect?
Antibodies
What is happening in an indirect ELISA?
- plate is coated w Ag
- Add primary Ab in serum
- Add 2nd Ab FROM A DIFFERENT SPECIES (Ex: Anti dog Ab) which is labeled w an enzyme
- Add substrate to bind to enzyme on 2nd Ab
- Look for color change
What does a sandwich ELISA detect?
Antigens
What is an example of when you would use immunoprecipitation assay?
To detect Type III hypersensitivity
** gives qualitative or quantitative results
How is precipitates formed?
Using equal amounts of Ab and Ag
*** Too much Ag or Ab = no precipitation
** Ab-Ag complex will form but rapidly dissociate
Is gel based immunoprecipitation a qualitative or quantitative assay?
Qualitative
How does gel based immunoprecipitation work?
Ag and Ab are put on seperate wells in an agar gel
- They diffuse towards each other
- At zone of equivalence Ag-Ab complexes form a precipitate in an arc or straight line
How can you tell blood groups in dogs and cats?
Blood typing
Ex: RBC containing A antigen on it is mixed with
Why are blood transfusions difficult in cats?
Because they naturally have anti-blood group antibodies
Ex: If type B blood - cats have high titers of Anti-A antibodies
If a cat w B blood gets a transfusion with A blood its game over , cat will have a strong rxn against it
What are the main blood groups in cats?
Types A, B and AB
** and Mik
What are clinically important RBC antigens in horses?
Aa
Qa
Ca
What techniques are available for blood typing?
- Typing cards
- Typing gels
- Membrane dipsticks
When is passive immunity necessary?
- During primary or secondary immunodeficiency
- When active immunity doesn’t develop to prevent disease
- In infections where best immunity is achieved through transfer of Ab
What diseases are examples of when passive immunity is administered?
- Rabies
- Botulism
- Measles
- Snake bites
-Diphtheria
What are the disadvantages of passive immunity?
- High possibility of a Type 1 or 3 hypersensitivity
- Immunity wanes with time
- No memory
How is hyperimmune serum made?
From serum collected from horses, sheep, and goats
What are the advantages of active immunity?
- Long lived immunity + effector T and B cells with memory
What are the advantages of a live-attenuated vaccine?
- Longer lasting effect than killed vax
- Replication of the pathogen increased the amt of Ag required to generate IR
- Antigenic epitopes are presented to T and B cells for Ab production
How is attenuation achieved?
- Passaging - virulent pathogen is cultured under conditions that dont support virulence (reduces virulence)
- Genetic engineering - by site directed mutagenesis or by removing genes responsible for virulence
What are methods used to kill or inactivate a pathogen intended for vaccine?
Heat, radiation, chemicals, antibiotics
What are subunit / component vaccines?
Made from purified Ag obtained from the pathogen
- Toxoids - purified toxins inactivated with formaldehyde but retain immunogenicity
- Bacterial polysaccharides - Ab against polysaccharides can opsonize bacT and result in efficient phagocytosis by neutophils + macrophages
