Immune Memory and Vaccination Flashcards
The immune response improves over time
- antibodies developed during the primary response provides protective immunity
- new adaptive immune response is not activated
- serum levels decline with time
what are the 3 adaptive memory cells
memory B cells
memory plasma cells
memory T cells
-central (in secondary lymph nodes)
-Effector (in the periphery)where can you find memory cells in the body(there are 4)
bone marrow(plasma cells)
secondary lymph nodes(central cells)
peripheral tissues(effector)
circulation
where do memory cells develop?
in the secondary lymphoid tissue
T/F memory cells mirror pathogen specific effector cells for example: Th17, CD4, memory T cells
True
characteristics of primary effector cells
broad antigen response multiple activation steps clonal selection and expansion under go target refinement -Somatic hypermutation -class switching cannot undergo hypermutation again die after several days
characteristics of memory cells
specific, restricted antigen response easily activated clonal expansion B cell target refinement unnecessary may undergo somatic hypermutation persist for months and replicate -long term immunity
Immune memory can persist for decades
pathogen and exposure-dependent
does not depend upon antigen persistence
steady-state serum antibody levels
persistence is highly variable across diseases
The secondary immune response does what to memory cells and what to naive B cells?
activate memory
inhibits naive cells
What happens when a naive B cells binds pathogen coated with specific antibody?
inhibits the naive B cell
What happens with a Memory B cell binds a pathogen that is coated with a specific antibody?
activates the memory B cell
Activated memory B cells replicate into plasma cells and more memory cells, can they form cognate pairs with memory Tfh cels?
yes
what happens when a memory B cell and a memory Tfh meet up?
form germinal centers class switch SMH **create a Ab with a now higher affinity for the antigen this is what vaccine boosters do
Memory T cells types
CD8 and all of the CD4 subtypes
do memory T cells require CD28 co-stimulation?
nope
what are the two classes of memory T cells
central memory cells (lymphoid organs)
effector memory cells (peripheral)
*the difference are the surface receptors
what do highly mutable pathogens do to immune memory?
erode it by mutations that occur in epitopes and the memory Abs will at some point no longer recognize the antigen.
primary response differences compared to secondary response
small number of pathogen specific cells at start
delay before pathogen-specific Abs are produced
-non-isotype switched Ab having a mixture of affinities for the pathogen
-high threshold of activation
-delay before effector T cells are generated and enter tissues
-innate immunity works alone until adaptive is started
secondary response differences compared to primary response
- large number of pathogen specific cells and response immediately
- pathogen specific Abs already present
- Abs are isotype switched and have high affinity for pathogen
- lower threshold for activation
- effector T cells are present and can enter infected tissues immediately
- close cooperation between innate and adaptive immunity
What do vaccines do to the immune cells
train immune memory highly effective can have rapid effect carries some risk herd immunity is important
vaccine targets
viruses bacteria parasites small molecules cancer autoimmune disorders
vaccine types
live attenuated inactivated subunit conjugate toxoid DNA recombinant vector
what was the first live attenuated live virus vaccine?
Cowpox
what is an attenuated virus?
shared viral components, but have no ability to infect humans
-weakened virus
what is an adjuvant?
a compound that incites an adaptive immune response
why are adjuvants added to vaccines?
broaden vaccine targets and improve efficacy by:
- response against typically non-reactive antigens
- enhances immune response
- Forces a thymus dependent Ab production
Recombinant protein vaccine
neisseria complement deactivation protein Abs
-taking genomes with unknown function and expressing them to develop a vaccine against and unknown target
what are some challenges for vaccine production
targets
evasion
mutation and variance
incidence and cost
