Vaccination Flashcards
What is a vaccine?
A substance used to stimulate the production of antibodies, and provide immunity against one or multiple diseases, prepared from the causative agent of a disease, products or a synthetic substitute, treated to behave as an antigen without inducing pathology
What is the principal aim of immunization?
To provoke immunological memory to protect the individual against a particular disease
What is an ideal vaccine?
Safe, easy to administer single dose, needle-free, cheap, stable, active against all variants and provides long-life protection
What is immune memory?
Improves the efficacy of the innate immune response. Focuses a response on the site of infection and the organism responsible, involves memory cells.
Where are memory cells stored?
Lymphoid organs or within the circulation
What does the primary response involve in terms of T & B cells?
Primary response requires differentiation and proliferation of naive T & B cells to facilitate appropriate TCRs & BCRs in addition to the production of specific antibodies complementary to particular antigen epitope
What is the main difference between a primary & secondary immune response?
The secondary immunological response is relatively quickly due to the presence of memory cells, thus grater production of antibodies (secondary expansion)
What are the correlates of protection?
Measurable signs that an individual or potential host is immune regarding protection against infection or developing disease
What is an example of a correlate of immunity?
Antibodies
What does the correlate of protection enable, clinicallY?
Enables smarter vaccine design, anti-F RSV antibody has driven the vaccine drive in RSV
Small efficacy studies (season flu vaccine roll out)
What are the two selection processes for b cells?
positive selection and negative selection
How does the negative selection of B cells occur?
Eliminates self-reacting B cells (apoptosis or induction of anergy in the B cell).
What does a BCR contain?
Light and heavy chains encoded by an individual gene.
How does mRNA splicing occur in terms of BCR recombination?
The primary RNA transcript is complimentary to the exons and introns present in the base sequence of the template strand. Intron sections removed from pre-mRNA transcript, and the exons undergo mRNA splicing
The recombination of exons results in various polypeptide sequences encoding for multiple immunoglobulin proteins. Regions shuffle and rearrange via recombination cell maturation, variable units are removed. VDJ recombinase enzymes involved
Which enzyme enables DNA recombination?
VDJ recombinase enzymes
Which VJD proteins are involved in light chain?
V & J
Which VJD proteins are involved in heavy chains?
V, J & D
Which region of the antibody determines the type of immunoglobulin?
Constant region
Alpha region = IgA
Where does BCR selection occur?
Bone marrow
Linked recognition caused which type of Th to be released upon activation?
Th2 secretes cytokines activate B cells and causes proliferation into clonal daughter cells
What role do Th2 cells have in terms of B cells?
Secretes cytokines and causes proliferation into clonal daughter cells - rounds of proliferation stimulates differentiation of activated B-cell clones into memory B cells and plasma cells
Which immunoglobulin is initially secreted by plasma cells?
IgM
What effect do Th2 cells have on plasma cells?
Stimulates plasma cells to switch from IgM production to IgG, IgA, IgE. Process of class switching or isotype switching - allows plasma cells cloned from same activated b cells to produce a variety of antibody classes
Which regions of the antibody are changed during isotype switching?
Genetic rearrangement of gene segments encoding the constant region (determines class) The variable region not changed, class retains original epitope specificity
Where does affinity maturation of b cells occur?
Germinal cells
What is the purpose of affinity maturation of B cells?
It generates high-affinity antibodies. Mutations resulting in gin alterations in the variable region to produce grater affinity antibodies