Innate Immunity Flashcards
What are biochemical components of system?
Complement
Type 1 interferons (alpha and beta)
What are cellular components of system?
Neutrophils Macs Nk cells Eosinophils Basophils Mast cells
What activates TLR 1 2 or 6?
Bacterial peptideglycan
Lipoprotein
Lipotechnoic acid
What activates TLR4?
Gram neg bacteria Lps
Fungal mannans
Viral envelop proteins
What activates TLR5?
Bacterial flagellin
What are the downstream effects of TLR activation?
Activates adaptor proteins and protein kinases
Then act. Transcription factors - nfkb or irf3
Then leads to gene transcription
Which expresses inflammatory cytokines (Tnf, IL-1 and 12)
Chemokines (IL8 MCP-1 RANTES)
E selection which is endothelial adhesion molecule
Costim molecule CD80/86
Antiviral cytokines IFN-a/b
Describe alternative pathway of complement
Activated by c3 binding to PAMP
Describe classical pathway of complement
IgM or IgG bins to antigen
What occurs upon initiation of complement system?
C3 cleaves to c3a and c3b
C3a responsible for inflammation also leads to mast cell degranulation
C3b responsible for opsonization and phagocytosis and leads to cleavage of c5
Describe the lectin pathway of complement
Mannose binding lectin (soluble PRR) in serum binds to mannose residues on microbes
What does mast cell degranulation achieve?
Releases histamine which increase vascular permeability and vasodilates.
What occurs upon cleavage of c5?
C5 cleaves to c5a and c5b
C5a leads to mast cell degranulation and attracts neutrophils (acts as chemokine)
C5b activates c6-9 to create MAC (membrane attack complex) leading to cell lysis
c9 creates the pore that lyses the cell
what is C3b?
an opsonin
what is C3a?
induces inflammation by inducing mast cell degranulation
What does C5b do?
binds to microbe membranes inducing c6-9 to bind and create a pore
What is the function of c5a?
induce degranulation of mast cells to cause inflammation
chemotatic for neutrophils
What is MAC?
membrane attack complex
its c6-9
What is interferon?
cytokine (in this case alpha or beta)
produced due to intracellular PRRs and travels to neighboring cells
stimulates neighboring cells to turn on genes for antiviral proteins for cell to make changes to protect itself
What enhances phagocytosis?
opsonins - c3b
IgG binds to Fc receptors on phagocytes
What enzymes are on the membrane of phagolysosome?
iNOS
Phagocyte (NADPH) oxidase
these make NO and ROS (OH-, peroxide)
What else do Macrophages do other then phagocytosis?
release cytokines for inflammation and to enhance adaptive immunity - cytokines
participate in wounding healing and tissue remodeling- FGF, angiogenic factors
What are the functions of NK cells?
recognize infected cells
releases Perforin and grazymes if cell does not have MHC I (which all normal cells have)
if cell does not have MHC I, then killing is not inhibited and the NK releases its cytolytic mediators
What stimulates endothelial cells to put up stop signs for neutrophils to infiltrate tissues?
Mast cell stimulate endothelial to put up stop signs
