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110 Cards in this Set
- Front
- Back
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In contrast to antibodies, interferons...
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Are not virus specific but host specific
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Species-specific proteins, which induce antiviral and antiproliferative responses in animal cells. They are a major defense against viral infections and abnormal growths (neoplasms)
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Interferons
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Why are interferons produced?
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In response to penetration of animal cells by viral (synthetic) nucleic acid and then leave infected cell
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What do interferons do for other cells in the body?
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Confer resistance from viral infections on other cells
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What is the only thing that inhibits viruses in humans?
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Human interferon
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What are the three different types of classification of interferon?
What is the larger class of proteins that interferons belong to? |
Alpha, Beta, Gamma
Cytokines |
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Proteins that carry signals between cells
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Cytokines
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What interferons have been used to treat various viral infections
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Alpha, Beta
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A current approved use for various types of interferon-alpha is in the treatment of what?
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Certain cases of acute and chronic hepatitis C and chronic hepatitis B
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Has been used to treat a variety of diseases in which macrophage activation might play an important role in recovery
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Interferon Gamma
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Due to interferons anti-proliferative effects what tumors have they been known to treat?
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Melanoma and kaposi's Sarcoma
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What immune system are interferons a part of?
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Non-specific immune system and integral as the first line of defense against viral infection
Activated early before the specific immune system responds |
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Interferons themselves _____ _____ antiviral antibodies. They interfere with virus _____.
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Are not
Replication |
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What cytokine stimulates hematopoiesis?
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Colony Stimulating Factor
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Family of small proteins that mediate an organism's response to injury or infection.
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Cytokines
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_____ are crucial to a n organism's self-defense.
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Cytokines
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Hoe do cytokines operate?
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Transmit signals between cells in small numbers by a specific cell type and regulate functions by binding to specific receptors
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A cytokines interaction with specific receptors causes the release of what to enhance the action of certain genes within the cell
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Secondary signals
Inhibit or enhance |
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How does the function of cytokines differ from endocrine hormones?
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Act locally near the cells that produce them.
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What produces an interferon Alpha and what is its function?
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- Buffy coat layer from white blood cells
- Treatment of a variety of malignant and immune disorders |
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What produces an interferon Beta and what is its function?
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- Fibroblasts
- Currently being evaluated in the treatment of multiple sclerosis |
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What produces an interferon Gamma and what is its function?
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- Activated T cells
- Important immunoregulatory molecule, particularly in allergic diseases |
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What produces Colony Stimulating Factor IL-3 and what is its function?
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- T Helper cells
- Stimulates a variety of hematopoietic precursors. being evaluated as a therapy in aplastic anemia and bone marrow transplantation |
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What produces Colony Stimulating Factor Granulocyte/Macrophage CSF and what is its function?
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- Lymphocytes, macrophages, fibroblasts, endothelial cells
- Regulate the selective production of neutrophils and macrophages |
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What produces Tumor Necrosis Factor TNFa and what is its function?
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- Activated macrophages
- Involved in the pathogenesis of septic shock and much research is aimed at trying to inhibit their activity in septic patients. Also treats human tumors |
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What produces Tumor Necrosis Factor TNFb and what is its function?
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- Activated T cells
- Involved in the pathogenesis of septic shock and much research is aimed at trying to inhibit their activity in septic patients. Also treats human tumors |
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What produces IL-4 and what is its function?
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- Monocytes, macrophages, T cells, B cells
- Causes T and B cells to grow. It's also a factor in the production of IgE antibodies |
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What produces IL-5 and what is its function?
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- Monocytes, macrophages, T cells, B cells
- Stimulates B cells and eosinophils. Causes B cells that produce IgA antbodies to proliferate |
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What produces IL-10 and what is its function?
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- Monocytes, macrophages, T cells, B cells
- Inhibits type 1 T Helper cells |
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Mediators of the cellular phases of inflammation and are potent vasodilators
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Prostaglandins
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Powerful vasoconstrictors and increase platelet aggragation
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Thromboxanes
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Important mediators of bronchial asthma
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Leukotrienes
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Vasodilator and reduces platelet aggregation
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Prostacyclin
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What acts as chemical messengers that is present in almost every body tissue and primarily act as local messengers that exert their effects on the tissues that synthesize them.
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Prostaglandins
Prostacyclins Thromboxanes Leukotrienes |
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A 20 carbon unsaturated fatty acid which is a major compound from which prostaglandins, prostacyclins, thromboxanes, and leukotrienes are derived.
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Arachidonic Acid
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What part of the cell is arachidonic acid found?
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Cell membrane
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What enzyme when activated splits arachidonic acid from the phospholipid cell membrane?
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Phospholipase A
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What enzyme is used to make prostaglandins, prostacyclins and thromboxanes from arachidonic acid?
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Cyclooxygenase from the cyclooxygenase pathway
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What enzyme is used to make leukotrienes from arachidonic acid?
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Lipooxygenase from the lipooxygenase pathway
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What is seratonin synthesized from?
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Amino acid tryptophan
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Where is Serotonin synthesized?
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Serotonergic neurons in the CNS
Enterochromaffin cells in GI tract |
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What is the two-step metabolic pathway that synthesizes Serotonin?
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1. Hydroxylation rxn (rate limiting)
2. Decarboxylation Rxn |
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The average adult human possesses only _____ of seratonin, _____ of which is in the intestine and the rest in blood platelets and the brain.
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5-10 mg
90% |
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What is serotonin widely considered to be?
What does it play a role in? |
Neurotransmitter
Temp. Regulation, Sensory perception, onset of sleep |
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What is the chemical name and abbreviation of seratonin?
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5-hydroxytryptamine
5-HT |
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These cells produce histamine and gastrin as well as seratonin .
What is an example? |
Enteroendocrine cells
Enterochromaffin cells (EC) |
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In the _____ _____ which lies deep at the center of the brain, serotonin is produced as a precursor to _____.
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Pineal Gland
Melatonin |
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Serotonin is a powerful _____
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Vasoconstrictor
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The function of serotonin in blood platelets _____ _____ _____; seems to have no important role in the clotting system
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Is not Clear
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Serotonin is secreted in tremendous quantities by what kind of tumors?
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Carcinoid tumors (tumors composed of chromaffin tissue)
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Serotonin acts as an inhibitor of pain in the _____ _____.
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Spinal cord
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What interferes with the action of Serotonin in the brain?
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Lysergic acid diethylamide
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Histamine is released largely by _____, causing vasodilation and bronchoconstriction.
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Mast cells and basophils
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How is histamine synthesized?
What catalyzes this reaction? |
By decarboxylation of amino acid histidine.
Enzyme L-histidine decarboxylase. |
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After it is synthesized where is histidine stored?
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Coarse cytoplasmic granules of mast cells and/or basophils
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What does histamine mediate in the early stages of acute inflammation ?
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Contraction of endothelial cells increasing vascular permeability
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Histamine is liberated by degranulation triggered by what two stimuli?
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1. Binding of specific antigen to membrane bound IgE
2. Binding of anaphylatoxins (C3a and C5b) to specific cell-surface receptors |
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Histamine is responsible for the principal symptoms of _____.
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Anaphylaxis
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What does histamine do to the blood vessels during inflammation?
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Vascular dilation and increases permeability
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Where are mast cells most commonly found?
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CT and extracellular spaces near blood vessels, esp. in the lungs/
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What is Histamine chemically similar too?
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Serotonin, Epinephrine, Norepinephrine
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Vasoactive kinin that mediates vascular permeability, arteriolar dilation, and pain. Potent vasodilator and produced by the action of _____ on an alpha 2 globulin. may be involved in blood pressure regulation.
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Bradykinin
(Pain from inflammation) Kallikrein |
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What is generated by activated Hageman factor, factor XIIa
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Kallikrein
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What is plasmin also known as?
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Fibrinolysin
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What is a proteolytic enzyme that is able to hydrolyze fibrin molecules and degrade other coagulation-related proteins, thus promoting dissolution of blood clots.
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Plasmin
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Where is plasmin normally found?
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Plasma in the form of the zymogen plasminogen (profibrinolysin)
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A plasma protein that is essential for the coagulation of blood and is converted to fibrin by thrombin and ionized _____.
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Fibrinogen
Calcium |
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Serves as a template for fibroblasts to repair tissue and walls of the infected area. The product the action of _____ on fibrinogen in the clotting process.
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Fibrin
Thrombin |
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When is prothrombin converted to thrombin?
What does this lead too? |
Presence of thromboplastin and calcium
Converts fibrinogen to fibrin |
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The inactive precursor to plasmin that is present in tissues, body fluids, circulating blood, and within clots
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Plasminogen
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An inactive enzyme precursor that needs to undergo some sort of biochemical modification to become an active enzyme. (Proenzyme)
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Zymogen
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What system plays an important role in regulating blood volume and systemic vascular resistance, thus influencing cardiac output and _____ _____?
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Renin-angiotensin-aldosterone system (RAAS)
Arterial Pressure |
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What are the three important components to the RAAS system?
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Renin
Angiotensin Aldosterone |
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What does renin stimulate the formation of?
Where? |
Angiotensin
Blood and Tissues |
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What does angiotensin stimulate the release of?
Where? |
Aldosterone
Adrenal Cortex |
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Renin is a _____ _____ that is released into circulation primarily by the kidneys.
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Proteolytic Enzyme
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What stimulates the release of renin?
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1. Sympathetic nerve activation (beta-1-adrenoreceptors)
2. Renal artery hypotension 3. Decreased sodium delivery to the distal tubules of the kidney |
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What is the circulating substrate in the blood that renin acts upon?
What does this form after proteolytic cleavage? |
Angiotensinogen
Angiotensin I |
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What is the enzyme in the vascular epithelium of the lungs that cleaves off two amino acids?
What does this make? |
Angiotensin Converting enzyme (ACE)
Angiotensin II |
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_____ serves a vital function in the transfer of energy within the cells
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Cytochromes
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Hemoproteins linked to a non-protein, iron-bearing component which can undergo the reversible oxidation-reduction reactions that yield energy for a cell
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Cytochromes
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What are the three classes of cytochromes that the mitochondria contains?
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A, B, C which all have hemes of different structures
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What is the heme group of a cytochrome made up of?
where is it located? |
Porphyrin ring containing an atom of iron.
Found in the mitochondrial inner membrane of eukaryotes |
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What does the iron atom of the heme group acts as in a cytochrome?
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Electron carrier
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How does the cytochrome iron atom differ from the heme groups of hemoglobin?
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Reversibly converts ferric (Fe3+) to ferrous (Fe2+) as a normal part of its function as a reversible carrier of electrons
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What are the mitochondrial electron transport proteins clustered into?
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Complexes I, II, III, IV
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What is the Enzymatic function and functional component of Cytochrome complex I?
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NADH/CoQ oxidoreductase
FMN; Fe-S clusters |
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What is the Enzymatic function and functional component of Cytochrome complex II?
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Succinate/CoQ oxidoreductase
FAD; Fe-S clusters |
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What is the Enzymatic function and functional component of Cytochrome complex III?
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CoQ-cytochrome c oxidoreductase
Cytochromes b, c1, Fe-S clusters |
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What is the Enzymatic function and functional component of Cytochrome complex IV?
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Cytochrome c oxidase
Cytochromes a and a3 |
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The terminal enzyme in the chain of events that constitutes cellular oxygen consumption.
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Cytochrome oxidase
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What interleukin favors TH-1 type responses and counteracts the action of IL-10?
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IL-12
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Sub-group of small soluble proteins called cytokines which function as chemical messengers between cells.
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Interleukins
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What is the role of interleukins?
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To mediate and control the immunologic and inflammatory response
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Similar to that of TNF; induce and promote the inflammatory reaction in gram-negative bacteria and other infectious microorganisms
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IL-1 from macrophages
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Stimulates the proliferation and activation of T cells and B cells.
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IL-2 from helper T cells
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Stimulates the growth and differentiation of hematopoietic cells, which mature into leukocytes, ganulocytes, erythrocytes, ect.
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IL-3 from T-cells
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Promotes B-cell activation and differentiation . it's also a factor in the production of IgE antibodies
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IL-4 from helper T-cells
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Stimulates B-cells and eosinophils . Causes B-Cells that produce IgA antibodies to proliferate
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IL-5 from helper T-cells
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Works in combination with interferon-alpha to induce B-cell differentiatio. Produces fever, stimulates helper T-cells
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IL-6 from T-cells and macrophages
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Causes lymphoid stem cells to differentiate into progenitor T- and B- cells.
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IL-7 from Stromal cells
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Sticky for T-cells and neutrophils and helps bring them to the site of inflammation
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IL-8 from Macrophages and Endothelial cells
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Inhibits the production of macrophage-derived TNF and IL-12, thus suppressing inflammatory reactions as well as the TH-1 pathway of T helper cell differentiation
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IL-10 from T- and B- cells, monocytes, and macrophages
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Favors TH-1 responses, with macrophage and NK cell activation; induces interferon gamma production
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IL-12 from Monocytes
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Stimulates IL-2 secretion and induces fever (pyrogenic)
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IL-1
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Stimulates proliferation of cytotoxic T-cells
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IL-2
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Stimulates bone marrow stem cells
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IL-3
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Stimulates chemotaxis and adhesion of neutrophils
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IL-8
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Cytokine which can induce apoptosis
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TNF-alpha
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What are the general properties of a cytokine?
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- Short half-life
- Active at low Conc. establishes conc. gradient - Able to operate on self (autocrine), nearby cells (paracrine), cells far away (endocrine) - Pleitropic: 1 acts on many cell types - Redundancy - Operate synergistically or antagonistically |
