Innate Immunity 2 Flashcards
Second Line of Defense
Ceullar Barrier
Cellular Barrier
Granulocytes
neutrophils/PMS
eosinophil
basophil
Macrophages
Dendritic cells
NK cells
Phagocytic Cells
Myeloid and Macrophage-monoctes
Myeloid
Neutrophil
Eosinophils
Basophil
Neutrophils
Rapid phagocytosis but cannot phagocytose repeatedly
Has granules which contains bactericidal enzymes
Short lived
No ability to present antigen
Macrophages and Monocytes
Slow but can phagocytose repeatedly
Contain bactericidal enzymes
Long lived
Selected cells have ability to present antigen
Granules in Neutrophils
Lysozymes
Myeloperoxidase
Superoxide dismutases
Lactoferrin
binds iron, therefore iron is not available for bacterial growth
Collagenase
dissolves collagen when entering tissues that have invaded antigen
Defensins
inserts between lipid bilayers and disrupt the interactions of lipid molecules
Increase in number of neutrophils
neutrophilia
Decreased number of neutrophils
neutropenia
Killing by neutrophils
phagocytosis
respiratory burst
extracellular traps (NETs)
Phagocytosis 4 stages
chemotaxis
attachment
phagocytosis
destruction
Chemotaxis
chemical signals that attract neutrophils to the site of inflammation
Adherence to vascular endothelial cells
increased expression of adhesion molecules on the surface of endothelial cells favoring attachment to surface molecules on neutrophils
Diapedesis
Neutrophils migrate out of blood vessel and enter injury site
Attachment
neutrophils and antigen attach to trigger igestion
zeta potential
both cell surface of phagocytes and antigens are negatively charged, therefore repel. Zeta potential needs to be reduced
opsonins
are proteins that bind to antigen to facilitate phagocytosis and decrease zeta potential. the process is called opsonization
Opsonin
any substances which promote phagocytosis
(ex. antibodies, complement components, certain liver proteins) natural ketchup-protein which coat the antigen to facilitate phagocytosis.
Phagocytosis
intesgtion
destruction
fusion of phagosome with lysosome-phagolysosome results in dumping of noxious antigen destroying chemical
Neutrophil extracellular traps (NETs)
sticky web-like nets made of de-condensed nuclear DNA
coated with antimicrobial protein from granules
shown to trap and kill bacteria are critical for clearing some infections
neutrophils form NETs and release them as a form of apoptosis (cell death) this is called NETosis
Eosinophil
Larger than neutrophils
increased in allergies and parasitic infestation
granules have arylsulfatase, peroxidase, acid phosphatase
Large crystalloid granule has core of major basic protein (MBP) with matrix surrounded by Eosinophil cationic protein (ECP)
Eosinophile peroxidase (EPO)
Eosinophil derived neurotoxin (EDN)
Basophil
Least numerous granulocyte (.5% of blood leukocytes)
granules have complex of vasoactive molecule
Macrophages
resting vs activated
Il-12
Stimulates Th-1
IL-10
Down regulates Th-1 immune responses
promotes some Th-2 and B cells
IL-6
Induces fever
promotes B cell functions
IL-1
stimulates T cells for antibody response
induces fever
Presentation of Antigen (Antigen presenting cells (APC))
- Slow responders
- Phagocytose repeatedly
- Select Cells can present antigen
they presents processed antigen to lymphocytes
Dendritic Cells- (thin membranous projections)
- Excellent antigen presenting cells (APC)
- antibody-coated antigens are rapidly presented to lymphocytes
4 types of dendritic cells
myeloid dendritic cell
lymphoid dendritic cell
follicular dendritic cell
plasmacytoid dendritic cells (looks like plasma cell, secrete IFNalpha
Type of T cell
helper
cytotoxic
memory
regulatory
types of B cell
memory
plasma
Natural Killer (NK) cells-Morphological features
subset of bone marrow-derived lymphocytes, distinct from B and T cells
express CD 16 (cluster of differentiation)
have cytotoxic granules containing special proteins like perforin and protease known as granzymes
Natural Killer (NK) cells-Functional features
Kill microbe infected cells by direct lytic mechanisms
kill tumor cells and viral infected cells
secrete IFNgamma
