Intro to Immune System Flashcards
conceptually the innate immune system is doing 2 thing.
- keep microbes out of normally stable body sites.
2. target microbes that get in with PAMPS
You need the innate immune system for the adaptive to work. what are some over arching roles of the innate immune system (2)?
- activate complement cascade to opsonize microbes, activate cells and to promote clearance of dead cells or Ab complexes.
- activates the adaptive immune system through antigen presentation (from APCs)
where does a lysozyme exert
it snaps the NAG-NAM bond in gram positive. it can work on gram negative after damage to the Outer Membrane
what are 4 defense mechanisms in the skin against microbes
- epidermis/ water resistant barrier
- dermal glands (sebum along hair, salt, pH)
- b-defensins, cathelicidins
- degradation of microbial nucleic acids (DNases, RNases)
where is lysozyme secreted in the gut mucosa
paneth cells
what are defensins
small, positvely-charged molecules that poke holes in microbes b/c microbial cell surfaces are negatively charged.. our cells tend to be negatively charged so defensins don’t really harm us
alpha defensins
a class of defensins that protect babies
beta defensins
found in the respiratory tract, kidneys, testes, and circulating
what are three things that are resistant to MAC?
noneveloped viruses, gram positive, fungi with outside cell wall (mycolic acid)
why doesn’t complement destroy out cells?
our cells are coated with molecules that diable MAC formation (Decay Accelerating Factor) DAF. some bacteria can do this too and enveloped viruses are using our cell membranes for their outer layer
what two things in bacteria all protect from complement?
biofilms, capsule
NK, B and T cells come from the lymphoid progenitor, what are it’s precursors
CD34 pluripotent stem cells which arise from myeloid progenitor
what are dendritic cells and monocytes derived from?
monoblast
what are the really good phagocytes
monocytes, neutrophils, and dendritic cells
what is the differences b/w a monocyte and a macrophage
monocyte is an immature macrophage– it’s going through the blood.
A macrophage is a tissue resident macrophage and are named basted on their location, they express CD14. monocytes are 2-6% of circulating leukocytes
tell me about dendritic cells
travel b/w tissue and regional lymph nodes as veiled cells.
capture antigen and bring it to consolidated T-cells
-present antigen for a long time
-express co-stimulatory molecules.
what are some things about neutrophils (PMNs) granulocytes?
-60-70% of PBL
-90% of circulating granulocytes
-Short half life= 6 hours, but hardy
-maturation via csf and IL-3
NOT APCs
primary granules of neutrophils
azurophilic- young neutrophils
Myeloperoxidase makes ROIs
secondary granules of neutrophils
specific for mature neutrophils. contains lysozyme
NADPH oxidase components make ROIs
mast cells enter the blood in precursor form and complete development in tissue under influence of local growth factors. what do their granules contain
histamine and heparin, but NOT hydrolytic enzymes.
