The Immune System 2 Flashcards
what occurs if the B cells fail to make a functional antibody?
apoptosis
where do functional B cells migrate to?
secondary lymphoid organs, lymph nodes and spleen
types of B cells
naive plasmablasts short lived plasma cells long lived plasma cells memory b cells
what are naive b cells
each with its own unique antibody receptor, when a naive b cell recognises its antigen, it proliferates/differentiates into plasmablasts
what are plasmablasts?
the most immature blood cell that is considered of plasma cell lineage - they are the first B cell to make antibody to antigen
what are short lived plasma cells
live as long as the infection lasts, producing large amount of secreted antibody
what are long lived plasma cells
mainly reside in the Bone marrow and GI tract and continue to make specific antibody of year-decades
what are memory b cells
reside mainly in the lymph nodes and spleen, here they spend their time improving the affinity and specificity of their antibody
Can live for our lifespan, depends on the pathogen infection
Will be reactivated if pathogen invades again
what does cell mediated immunity target?
infected viral cells and cancers
what are APCs
macrophages and dendritic cells
They phagocytose and kill pathogens and present fragments of the pathogens as antigens to T cells
types of T cells
helper, cytotoxic, NK
what do helper T cells do?
produce cytokines that enhances the activity of B cells, CTL cells and phagocytes
what do cytotoxic T cells do?
attacks and kills virus infected cells and cancer cells
what does humoral immunity involve?
B cells that differentiate into antibody secreting plasma cells
what does cellular immunity involve?
T cells that differentiate into helper or cytotoxic t cells
what do t cell recognise
antigenic peptides that are presented by MHC molecules on APCs
when do t cells recognise antigens
when presented by APCs
Live Attenuated Vaccines LAV
Eg live oral polio vaccine
Advantages: virus causes mild infection, immunity is good as very close to virus encountered in natural infection
Subunit vaccines (recombinant protein)
Usually derived from outer surface of pathogen
Viral capsid/envelope protein or bacteria surface protein
Advantages: no live component , no risk of inducing illness, purified protein used- chemically defined, safe and more stable than LAV
Disadvantages: more expensive, may be less immunogenic than LAV
Eg V. cholera B subunit vaccine, hep B , HPV
VIRUS VECTOR Vaccines
A live vector vaccine is a vaccine that uses a weakened or non human pathogen virus to transport a peice of the pathogen in order to stimulate an immune response to the pathogen protein
Used to develop EBOLA vaccine
how many antigen binding sites does IgM have
10
where is IgG found
lymph and blood
what do cytokines do?
Loss of T follicular helper cells
No stimulation of B cells in GCs
Wasting away of GCs
Great reduction of long term B cell memory
how do antibodies work?
a) neutralization
b) opsonization - coating/encapsulation of a pathogen
c) complement activation -
