SECRETS Immuno - Basics Flashcards
primary lymphoid organs
bone marrow = B & T
thymus = T
fetal liver
where lymphocytes mature
secondary lymphoid organs
appendix
tonsils
peyer’s patches
mature lymphocytes respond to antigens on APCs
innate immunity
first line of defense
nonspecific
PRRs –> recognize PAMPs
prevent microbes from entering
destroy/limit growth
neutrophils, macrophages, eosinophils, basophils, mast cells, NK cells
adaptive immunity
B, plasma cells
helper T, cytotoxic T cells
specific, memory
bridge from innate – adaptive
dendritic cells
cell mediate immunity
helper t Cells
vs virus, fungi, mycobacteria
type IV hypersensitivity, tumor destruction, graft rejection
MHC class I
all nucleated cells
interact with CD8+ T cells –> destruction
display nonself peptides that have been processed intracellularly
MHC class II
APCs = dendritic cells, macrophages, memory b cells
interact with CD4+ T cells –> upregulate Th cytokine production –> macrophage activation, plasma cell proliferation
display exogenous nonself peptides obtained via phatocytosis, endocytosis
ADCC
bing IgG to Fcy receptors
destruction via phagocytes or NK cells
IgA
mucosal immunity
poor activator of complement
IgD
on mature B cells
unclear role
IgE
on tissue mast cells and blood basophils
mediate type I hypersensitivity
parasitic killing via ADCC
IgG
in blood, crosses placenta longest half life ligand for Fc receptors activate classical complement pathway most abundant Ig in secondary immune response highest affinity (strength)
IgM
in blood, pentamers
activate classical complement pathway
earliest Ab produced
most abundant Ig in primary immune response
highest avidity (number of binding sites)
neutrophil chemotaxis
IL-8
C5a
LTB4