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Immunology Lecture 3
Lecture Outlines, Slides, and Scribes
18
Medical
Graduate
08/27/2009

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Cards

Term
What cytokine causes APPs to be released? What are some examples of APPs?
Definition

IL-6 induces the liver to produced acute phase proteins (APPs).

 

1) CRP (C-Reactive Peptide) - binds to C protein/phosphorylcholine on bacterial surfaces, i.e. Pneumococci

- acts as opsonin and activates complement system

 

2) Mannin-binding lectin - opsonin and activates complement

 

3) Alpha-2 macroglobulin

 

4) Serum amyloid protein

 

5) Fibrinogen

Term
What are some examples of PRRs?
Definition

Pattern Recognition Receptors:

 

1) C-type lectin receptors - binds carbs

 

2) Toll-like receptors

Term
Describe the function of TLR-2, -3, -4, and -9.
Definition

Toll-like receptors

 

TLR-2: recognizes variety of bacterial components

 

TLR-3: recognizes double-stranded RNA

 

TLR-4: receptor for bacterial lipopolysaccharide (LPS)

 

TLR-9: receptor for bacterial and viral non-methylated DNA sequences (CpG)

 

TLR-3, 7, 8, 9 are expressed in endosomes; others on cell surfaces

Term
True or false. Macrophages and neutrophils engulf bacteria and present the antigens to CD4 T cells.
Definition
False. Neutrophils do not usually present antigens.
Term
What happens when the mannose receptor is bound?
Definition

Production of cytokines and reactive oxygen species.

 

Also, phagocytosis of microbes.

Term
Which phagocyte membrane receptor associates with CD14, the receptor for bacterial lipopolysaccharide (LPS)? What will binding of this receptor do?
Definition

TLR4 - kills gram + bacteria

 

Activation will increased production of cytokines and reactive oxygen species

Term
Which phagocyte membrane receptor senses chemokines, N-formlymethionyl peptides, lipid mediators (antigens given off by bacteria)? What will activation of this receptor do?
Definition

Seven alpha-helical transmembrane receptors

 

Activation will lead to changes in the cytoskeleton and migration of phagocyte to the tissues.

Term
What are the characteristics of a phagocyte undergoing metabolic burst?
Definition

1) Increase oxygen consumption

2) Activation of hexose-monophosphate shunt

3) Activation of NADP system

4) Increase glycolysis

Term
When macrophages recognize CpG sequences, what cytokines are produced?
Definition

IFN-alpha, IFN- beta, IL-12

 

CpG sequences are bacterial DNA that are present intracellularly

Term
Describe the oxygen-dependent system of lysosomal discharge and respiratory burst. How is this system upregulated?
Definition

Phagocyte oxidase system --> generates free radicals

 

Upregulated by IFN-gamma, and TLR signaling

Term
Describe the oxygen-independent system of lysosomes.
Definition

1) Lactic acid (from glycolysis)

2) Lysozyme (cleaves beta-1,4 linkages in carbs)

3) Lactoferrin - competes with microbes for iron

4) "Defensins" - phagocytin and leukin - detergent-like (pH 7)

Term
What cytokines/molecules induce macrophages to secrete nitrogen oxide?
Definition
LPS and IFN-gamma
Term
What cytokines are secreted by NK cells? What kind of receptor is on its surface which allows it to be part of ADCC?
Definition

Cytokines: IFN-gamma (activate macs), GM-CSF, TNF

 

Receptor: CD16 - FcR (Fc region receptor) for IgG

Term
What is the "missing self" paradigm of NK cells? How do they lyse the target cells?
Definition

MHC I engage killer inhibitory receptors (KIR). If target cell does not have MHC I, killer activating receptors (KAR) will no longer be inhibited by KIR and NK cells will kill.

 

They kill via perforins, proteases --> apoptosis of other cell (like CTL)

Term
What cells produce IFN-alpha and beta? What cells produce IFN-gamma?
Definition

IFN-alpha, beta: made by leukocytes, dendritic cells (plasmacytoid dendritic cell, PDC), monocytes and fibroblasts

 

IFN-gamma: CD4 T cells, NK cells

Term
What cells secrete TNF-alpha? What is its function?
Definition

Activated macrophages and NJ cells.

 

Endotoxic shock, inflammation, immunoregualtion, antiviral responses.

Term
What cells secrete IL-12? What does it do?
Definition

Produced by monocytes and other APCs (esp. Type I dendritic cells)

 

Stimulates cytotoxic cell activity and proliferation of T and NK cells.

 

NOTE: Major link between innate and adaptive immune systems --> develops TH1 response

Term
What cells secrete IL-6? What does it do?
Definition

Produced by macrophages, T cells, endothelial cells

 

Increases bone marrow production of neutrophils and stimulations production of fibrinogen, CRP.

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