B Cell Vaccines Flashcards
Types of vaccine
- live attenuated
- whole killed/ inactivated
- subunit (recombinant/polysacc)
- viral vector
- DNA vector
What is an adjuvant?
A substance that, when added to a vaccine, greatly enhances its protection against infection
What does an adjuvant help to do?
- decreases the amount of antigen required for activation
- safe
- effective
- lower vaccine doses
4 main mechanisms of adjuvants
- depot effect
- PRR activation
- inflammosome activation
- MHC activation
Technologies for vaccine development
- empirical approach
- recombinant DNA
- glycoconjugation
- reverse vaccinology
- next-generation technologies
What does B in B cell stand for?
Bursa of Fabricius
What are epitopes
Ant-body binding sites
Type of immunity
- active immunity
- passive immunity
What is active immunity?
Permanent protection produced by the person’s own immune system
What is passive immunity?
Temporary protection transferred from another person or animal
What is an active vaccine?
Stimulates the host’s immune system to produce specific antibodies or cellular immune response or both which would protect against or eliminate a disease
What is a passive vaccine
A preparation of antibodies that neutralizes a pathogen and is administered before or around the time of known or potential exposure
Features of effective vaccines
- safe
- protective
- gives sustained protection
- induces neutralizing antibody
- induces protective T cells
- practical considerations
Determinants of primary vaccine Ab responses in healthy individuals
- vaccine types
- antigen nature
- vaccine schedule
3 type of antibody binding specificities
- perfect fit
- no fit
- poor fit
Ab functions
- neutralization
- complement fixation
- agglutination
- opsonization
- antibody dependent cell mediated cytotoxicity
How does ADCC work?
- target cell covered with AB (Fc portion sticking outwards)
- CD16 expressed on NK cell surface
- cross-linking of Fc receptors induces rapid release of cytoplasmic granules
- used to destory large organisms that cannot be phaogcytosed
How to measure ADCC
- chromium release assays
- luminescent readout
Types of antigen
- T-dependent antigens
- T-independent antigens
How do TD antigens work?
- activate via BCR but depend on additional signals from helper T cells to cause division/differentiation
- protein anitgen
How do TI antigens work?
- induce division/differentiation by BCR signaling without MHC class II T help
- bacterial polysaccharides, repeating subuits
Define somatic hypermutation
A unique mutation mechanism that is targeted to the variable regions of rearranged Ig gene segments
What is a toxoid?
Bacterial exotoxins can be modified genetically or by chemicals such as formaldehyde to disrupt the toxin’s active site
Describe polysacharide vaccines
Unique type of inactivated subunit vaccine composed of long chains of sugar molecules that make up the surface capsule of certain bacteria
How does a congugated polysaccharide vaccine work?
Hib vaccine generates Ab response against polysaccharide through T cell recognition and B cell activation of linked tetanus toxoid protein antigen
- switches B cell response from TI to TD
Advantages of ELISA
- robust and relatively accurate
- sensitive and specific
- relatively cheap
- reproducible
- excellent for high-throughput
Disadvantages of ELISA
- provides no info about cell source of analyte
- only measures 1 thing at a time
- high volume of sample required
Steps of ELISA
- coat plate with capture antigen
- add primary antibody
- secondary antibody (enzyme linked)
- add substrate
- covnert OD to conc values
Steps of ELISpot
- coat nitrocellulose membrane with capture antigen
- add and stimulate cells
- secreted Ab binds
- add secondary antibody
- read and count spots
