Cellular Immune response Flashcards
What are the 4 types of effector CD4+T cells
TH1
TH2
Tfh
regulatory cells
What happens after a cell becomes selected
clonal expansion
How does a cell become active (selected)
binding of specific antigen
co-stimulation
What occurs after clonal expansion
differentiation
What can differentiate into
Effector cells
Memory cells
Where do Th1 cells go to
migrate out of lymph
enter into infected/inflammed tissues
How do macrophages become ‘super-activated’
Macrophages in tissues
inflammatory signals direct Th1
binds to macrophage via MHC2
release interferon gamma
Why do we need improved macrophages rather than neutrophils?
Some pathogens have evolved to escape phagosome
Th1 induces production of ROS
What cytokine is responsible for inducing the NADPH complex in macrophages
interferon gamma
What does the interferon gamma signal
the production and release of ROS into the phagolysosome
What is the function of Tfh
Drive high affinity antibody response
What occurs after B cells are reactivated
Will differentiate into long lived plasma and memory cells
What do CD8+ T cells differentiate into
Cytotoxic T cells
How do cytotoxic T cells identify target cells
Finds cells displaying non-self antigens in tissues etc via MHC class 1
How do cytotoxic T cells eliminate other cells
granules with apoptosis inducing agents
How are cytotoxic T cells activated
Scans viral peptide on MHC 1
Examples of granules found in cytotoxic T cells
perforin
granzymes
Granulysin
How does killing by cytotoxic T cells not promote further inflammation
contents of cell killed by apoptosis is contained, proteins etc are not released so inflammation is not promoted
What happens to effector cells after the immune response has finished
will die off naturally due to short life span
What do long life plasma cells do after the immune response has finished
continually secrete low levels of high affinity antibodies
Why is the number of antigen specific T/B cells higher to one specific antigen than at the beginning
specific immune cell has undergone proliferation, so now there is a slightly higher number
Why do inflammatory mediators die quickly after immune response ends
short half-life
What happens to acute phase proteins after the immune response has finished
rapidly disappear due to short half life
what do macrophages phagocytose at the resolution stage
cellular debris
secrete factors to dampen inflammatory response
