Cykines In Health And Disease

Question 1

what do cytokines do?

Answer 1

serve as chemical messengers of the immune system

Question 2

are cytokines antigen specific?

Answer 2

no

Question 3

true/false: cytokines are glycoproteins that act over only short ranges

Answer 3

false: act over short and long ranges and can therefore result in systemic effects
they are glycoproteins

Question 4

how do cytokines exert their functional effects?

Answer 4

bind to specific receptors on the target cell

Question 5

cytokines have ______________________, meaning that one cytokine can affect the activity of many different target cell types

Answer 5

pleiotropic properties

Question 6

what is functional redundancy?

Answer 6

more than one cytokine (or other signal) can act on a single cellular target

Question 7

what does autocrine mean with cytokines?

Answer 7

a cytokine can act on the same cell that secreted it

Question 8

what are the two results of the fact that cytokines rarely act alone in vivo?

Answer 8

synergistic effects: work together to create a bigger effect than the sum of the two
antagonistic effects: one cytokine inhibits the activity of another

Question 9

what do interleukins (IL) do?

Answer 9

regulate interactions between leukocytes
can act on other cell types

Question 10

what do interferons (IFNs) do?

Answer 10

interfere with viral replication within host cells
also other functions

Question 11

what interferons (IFNs) are in each class?

Answer 11

type I: IFN-alpha and IFN-beta
type II: IFN-gamma

Question 12

what do tumor necrosis factors (TNFs) do?

Answer 12

cause necrosis by inducing local inflammation and thrombosis of tumor blood vessels
potent mediators of acute inflammatory response to infectious agents

Question 13

what cells stimulate the expansion and differentiation of bone-marrow progenitor cells?

Answer 13

colony-stimulating factors (CSF)

Question 14

what are two types of chemokines and what do they do?

Answer 14

affect leukocyte movement
monocyte chemotactic protein-1 (MCP-1) attracts monocytes
interleukin-8 (IL-8) attracts neutrophils

Question 15

what are the primary mechanisms utilized by the innate immune system to combat extracellular bacteria?

Answer 15

complement activation
phagocytosis
inflammatory response

Question 16

what do macrophages produce in response to bacterial products?

Answer 16

TNF-alpha
IL-1
chemokines

Question 17

what acts on vascular endothelium to induce the expression of adhesion molecules at the site of infection?

Answer 17

TNF-alpha and IL-1

Question 18

what induces the secretion of IL-8 by endothelial cells?

Answer 18

action of TNF-alpha and IL-1 on vascular endothelium

Question 19

what does TNF-alpha stimulate in neutrophils?

Answer 19

microbial activities

Question 20

what induces fever?

Answer 20

TNF-alpha and IL-1 lead to increase synthesis prostaglandin E2 (PGE2) which acts in the hypothalamus

Question 21

what is prolonged production of TNF-alpha associated with?

Answer 21

cachexia

Question 22

how do macrophages and dendritic cells respond to intracellular bacteria?

Answer 22

secrete IL-12 which induces local production of IFN-gamma (produced by natural killer cells)

Question 23

what do macrophages do after being exposed to IFN-gamma?

Answer 23

destroy phagocytized bacteria present in phagosomes or phagolysosomes

Question 24

what does cytokine-mediated innate immunity against viruses consist of?

Answer 24

inhibition of infection by type I IFNs
NK cell-mediated killing of virus-infected cells

Question 25

what do IFN-alpha and IFN-beta do to infected and neighboring uninfected cells?

Answer 25

cause them to synthesize a number of enzymes, which interfere with viral transcription and replication uninflected host cell that has responses to these and is resistant to viral infection is in “antiviral state”

Question 26

what stimulates the proliferation and cytotoxic function of NK cells?

Answer 26

IL-15 IL-12

Question 27

what determines the differentiation of a naive CD4+ T cell into a particular Th cell subset or induced Treg?

Answer 27

cytokines secreted by the innate immune response not random process

Question 28

what does IL-12 induce naive Th cells to do?

Answer 28

differentiate towards Th1 subset which produce IFN-gamma and TNF-alpha

Question 29

what does IFN-gamma do?

Answer 29

promotes Th cells to differentiate into Th1 activates macrophages to kill promotes class switching in B cells

Question 30

what are the most important cytokines that lead to cytotoxic T lymphocyte responses against intracellular microbes?

Answer 30

IL-12 and/or type I IFNs

Question 31

when an intracellular pathogen can induce strong innate cytokine responses ie strong IL-12 and/or type I IFN responses, help from _____________________ to generate ____________________ is not required

Answer 31

Th1 cytokines CTL responses

Question 32

true/false: the Th1 pathway is known to facilitate cell-mediated or cellular immunity

Answer 32

true

Question 33

what does Th2 differentiation occur in response to and what do they produce?

Answer 33

antigens IL-4, IL-5, IL-13

Question 34

what are the functions of IL-4?

Answer 34

differentiation Th to Th2 stimulates B cell Ig heavy chain class switching to IgE class switching to IgG subclasses

Question 35

what type of immunity is the Th2 pathway known to facilitate?

Answer 35

humoral immunity

Question 36

what type of immunity is the Th1 pathway known to facilitate?

Answer 36

cell-mediated or cellular immunity

Question 37

what is the key cytokine that Th17 cells produce?

Answer 37

IL-17

Question 38

what does IL-17 do?

Answer 38

stimulates TNF-alpha, G-CSF, neutrophil chemotactic chemokine IL-8 production antimicrobial peptides

Question 39

what do induced or adaptive regulatory T cells (Tregs) produce?

Answer 39

TGF-beta and IL-10 which suppress inflammatory response

Question 40

what is sepsis?

Answer 40

bacterial infection in bloodstream or body tissues

Question 41

what is septic shock or endotoxin shock?

Answer 41

from sepsis cardiovascular collapse, disseminated intravascular coagulation, and hypoglycemia

Question 42

what happens in septic shock to IL-1 and TNF-alpha?

Answer 42

too much cause systemic clinical and pathological abnormalities

Question 43

what does TNF-alpha do that leads to shock?

Answer 43

increased expression pro-coagulation protein and decreased expression anti-coagulation proteins on endothelial cells

Question 44

what does nitric oxide do to the heart?

Answer 44

produced by cardiac myocytes inhibition myocardial contractility and leads to heart failure

Question 45

true/false: systemic inflammatory response syndrome (SIRS) is related to organ failure due to the escape of fluid from blood into extra vascular space which leads to organ dysfunction and failure

Answer 45

true

Question 46

what is acute respiratory distress syndrome caused by?

Answer 46

leakage fluid into lungs

Question 47

what cytokines are produced in superantigen-mediated toxic shock?

Answer 47

IL-1 and TNF-alpha by macrophages also others

Question 48

true/false: a cytokine generally binds with a few different types of receptors on the surface of a cell to exert its function(s)

Answer 48

false: only one type of receptor

Question 49

true/false: some cytokines can have endocrine action. for example, they can get into the blood stream and act on the bone marrow progenitor cells

Answer 49

true

Question 50

true/false: both Th1 and Th2 responses can lead to class switching to IgG type of antibodies

Answer 50

true

Question 51

true/false:IL-8 cytokine can help neutrophils with locating pathogens in an inflammatory site

Answer 51

true: IL-8 attracts neutrophils and MCP-1 attracts monocytes

Question 52

true/false: effects of IFN alpha and IFN beta lead to an antiviral state in uninfected cells

Answer 52

true

Question 53

what is the function of IL-5?

Answer 53

activates and stimulates differentiation and growth of eosinophils

Question 54

what is the function of IL-13?

Answer 54

stimulated mucus production of goblet cells of airways and gut

Question 55

what is the function of IL-4 and IL-13 together?

Answer 55

stimulates peristalsis of gut to promote elimination of helminths

Question 56

what is the Th2 pathway known to facilitate?

Answer 56

humoral immunity

Question 57

with extracellular bacteria in tissues, macrophages respond to bacterial products by producing ________________________________________

Answer 57

TNF-alpha, IL-1, and chemokines

Question 58

what do TNF-alpha and IL-1 stimulate?

Answer 58

extravasation microbicidal activities neutrophils (only TNF-alpha) IL-8 (attracts neutrophils) fever (prostaglandin E2)

Question 59

in viral infections, ______________ are secreted by the virus-infected cells, and APCs

Answer 59

type 1 interferons (IFN-alpha and IFN-beta)

Question 60

IL-15 stimulates the ________________ of NK cells IL-12 enhances the ________________ of NK cells

Answer 60

proliferation cytotoxic function

Question 61

IL-12 induces naive Th cells towards the ______ subset, which produces ____________

Answer 61

Th1 IFN-gamma and TNF-alpha

Question 62

what induces recruitment of leukocytes and inflammation?

Answer 62

TNF-alpha

Question 63

______ differentiation occurs in response to antigens

Answer 63

Th2

Question 64

Th2 cells produce _________________________

Answer 64

IL-4, IL-5, IL-13

Question 65

what does IL-5 do?

Answer 65

activates eosinophils and stimulates growth/differentiation

Question 66

____ differentiation occurs in response to extracellular bacteria and fungi

Answer 66

Th-17