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51 Cards in this Set

  • Front
  • Back
Where are HSC are located?
In the yolk sac during early embryonic stage, in the liver during early periods of gestation, and in bone marrow for the rest of the life
What are Peripheral or Secondary Lymphoid Organs ?
Peripheral or Secondary Lymphoid Organs are Concentrated sites of lymphoid tissue where mature lymphocytes have a chance to get stimulated to respond to invading pathogens. Examples for above: Spleen, Lymph Nodes located in various places of the body, Loosely organized mucosal associated lymphoid tissue, including payer?s patches, adenoids, tonsils.
Mature "naive" B and T cells, unlike other blood cells, continuously circulate from blood to lymph nodes and back into blood. T/F
Give the pathway that Lymphocytes take in the lymphatic syst:
Lymphocytes enter lymph nodes via arteries, but exit via Efferent Lymphatics, and finally re-enter blood circulation through left subclavian vein
Once antigen encounter occur the microbe specific T cells undergo clonal expansion and effector differentiation in what?the
lymph node
Some of these effector T cells travel to infected tissue via what?
efferent lymphatics and blood
some of the effector T cells remain in lymph nodes and help B cells differentiate into antibody secreting plasma cells T/F
The antibodies travel to infected tissues via what?
efferent lymphatics and blood.
In the case of blood borne infections what acts as secondary lymphoid tissue where adaptive immunity is initiated?
the spleen
Concentrated areas of the lymphocytes?
White pulp
Old/damaged RBC removed from circulation?
Red Pulp
In the case of infections coming from mucosal surfaces what acts as secondary lymphoid tissue where adaptive immunity is initiated?
mucosa associated lymphoid tissue (MALT)
Immune memory is a unique character of the innate or adaptive immune system?
adaptive immune system
White Blood Cells=?
Lymphocytes= ?
T and B cells (usually circulate between blood, spleen and Lymph nodes, but alter circulation when stimulated)
Na‹ve or virgin lymphocytes=?
the T and B cells that have not yet been stimulated.
Granulocytes (rich in granules) =?
Polymorpho nuclear lymphocytes or PMNL (have multi-lobbed nucleus)= Neutrophils, Eosinophils, Basophils (usually in blood but called upon to site of infection when needed, do not usually enter lymph nodes)
Phagocytes= ?
Usually Macrophages and Neutrophils but dendritic cells can do some phagocytosis although not as efficiently
Precursor cells of the macrophages and dendritic cells. These cells circulate in blood and mature into macrophages or dendritic cells upon tissue entry.
What do Paneth cells do?
constitutive secretion of definsins (part of innate immunity)
What are PRRs?
Pattern Recognition Receptors
What are PAMPs?
Pathogen Associate Molecular Patterns (ex: Gram +/_ bacteria, viral: Surface glycoproteins, protein-associated lipids, capsid protein, Nucleic acid (ssRNA, dsRNA, B-DNA)
What is the relationships between PRRs and PAMPs?
PRRs in the host recognize PAMPs in the microbe
NOD-like receptors (NRLs) are NOT cytoplasmic T/F
What is essential for innate immune gene expression?
NF-KB activation drives cytokine mRNA expression.
What happens to patients without functional IRAK4?
They suffer from recurrent infections with encapsulated bacteria. In contrast they maintain good response to most common viral infections
What are Retinoic acid inducible gene I (RIG-I) and Melanoma differentiation antigen 5 (MDA5)?
Specifically binds viral RNA: RIG-I binds ssRNA and short dsRNA, MDA5 binds to long dsRNA and Contain N-terminal caspase recruitment (CARD) domain
what are Definsins?
membrane-penetrating peptides that disrupt
and destroy microbes
what do Kinins (bradykinin) do?
what are protease inhibitors?
blockage of microbial invasion
what cells secrete definsins constitutively?
paneth cells in the gut
(Pattern Recognition Receptors) In the host recognize
the activation of complement cascade
is triggered by the recognition of what?
structural and space orientation patterns of the mannose sugar residues on microbial membranes and initiates
what are Toll-like receptors?
Type I transmembrane receptors characterized by extracellular leucine-rich repeat (LRR) domain and intracellular Toll/IL-1 receptor (TIR) domain
what does myD88 bind to? result?
IRAK4- synthesis and secretion of TNF-alpha and other inflamatory cytokines
what does TRIF bind to? result?
TRAM; synthesis and secretion of type one interferons - INF- alpha and beta. leads to anti viral response
what are the key players Systemic IFN production?
epithelial cells and plasmacytoid dendritic cells
Do not kill our self cells because our cells express
NK inhibitory ligands, and lack NK activating ligands T/F
When there is an infection or stress, what is up-regulated and down regulated in our cells?
1. molecules that give inhibitory signals to NK cell (e.g., decreased MHC class-I expression after herpes virus infection) are down-regulate
2. molecule that activate NK cells
(e.g., expression of MIC-A & MIC-B in stressed cells are up-regulate
what secretes IFN-g and what does this molecule do?
-NK cells
-IFN-g induce macrophages to kill the phagocytosed bacteria.
IFNs and IL-12 DO NOT activate NK cells. T/F
F. IFNs and IL-12 activate NK cells
What is the arachidonic acid pathway?
one of the main mechanisms for the production of pain and inflammation, as well as controlling homeostatic function. The pathway produces different classes of end product:
The prostaglandins (from cyclooxygenase metabolism) (PG) esp PGE2, PGF2alpha and PGD2
2. The Prostacyclines PGI2 3. Thromboxane Tx A2 4. The leukotrienes ( from lipoxygenase metabolism)
What are prostaglandins?
mediators of the vascular phases of inflammation and are potent vasodilators. They increase vascular permeability.
What does Aspirin (Acetyl Salicylate) inhibit? How?
It inhibits prostaglandin synthesis by blocking the cyclooxygenase pathway
How is inflammation signaled in response to
PAMP recognition?
NF-kB activation and inflammasome induction

Activation of responsive transcription factors,
IRF-1, IRF-5, AP-1, others.. (cell-specific)
what is an inflammasome?
An antimicrobial innate immune defense that is mediated by
-Nod-like receptors (NLRs) or other signaling receptors

-A multiprotein complex that activates caspase-1

-A platform that leads to caspase-1 activation,
processing and secretion of key pro-inflammatory cytokines such
as IL-1β, IL-18 and IL-33. IL-1b is chief for initiating and propagating inflammation.
what is diapedesis?
squeezing through endothelium
what can a defective NADPH oxidase subunits cause in a patient?
Patients with defective NADPH oxidase subunits lack respiratory burst
-> no pH raise in the pahgosome
-> microbes not killed in the
->microbes persist as chronic intracellular infections
->Form localized nodules that contain infection, called granulomas
give an example of NK inhibitory and activating receptor
What recognizes class 1 MHC receptors (on any cell)?
CD8 T cell (recognizes intracellular pathogens)
What recognizes class 2 MHC receptors (on APCells)?
CD4 T cell (recognizes extracellular pathogens)