6/27 - Diseases of Immune System

Question 1

what type of organs are tissues of the immune system

Answer 1

generative and peripheral organs

Question 2

what are generative organs

Answer 2

thymus and bone marrow

Question 3

what are the peripheral organs

Answer 3

lymph nodes, spleen, mucosal tissues, and cutaneous lymphoid tissues

Question 4

what is the function of MHC molecules

Answer 4

to bind peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T cells

Question 5

! T/F: MHC are proteins and its lower most unit are molecules

Answer 5

TRUE

Question 6

Is T-cell recognition of antigens MHC restricted?

Answer 6

YES

Question 7

how are MHCs deleterious to the pathogen

Answer 7

1. virus-infected cells are killed
2. macrophages are activated (to kill bacteria in their intracellular vesicles)
3. B cells are activated (to produce antibodies that eliminate or neutralize extracellular pathogens)

Question 8

T/F: even if a pathogen has mutated, it DOES NOT escape presentation by an MHC molecule

Answer 8

FALSE! it does escape MHC presentation

Question 9

what properties of MHC make it difficult for pathogens to evade immune responses (what makes it special)

Answer 9

1. polygenic
2. polymorphic

Question 10

what does it mean for an MHC to contain several different MHC class I and MHC class II genes, so that every individual possesses a set of MHC molecules with different ranges of peptide-binding specifities

Answer 10

polygenic

Question 11

what does it mean for an MHC to have multiple variants of each gene within the population

Answer 11

polymorphic

Question 12

what are the most polymorphic genes known

Answer 12

MHC genes

Question 13

when is the only time cell surface proteins/MHCs are identical?

Answer 13

identical twins

Question 14

what contributes to the diversity of MHC molecules expressed by an individual

Answer 14

polymophism an polygeny

Question 15

polymorphism of MHC molecules is a critical importance in antigen recognition by ___

Answer 15

T cells

Question 16

T cell recognizes antigen as a peptide bound by a particular allelic variant of an MHC molecule and will not recognize the same peptide bound to other MHC molecules. What is this behavior of T cells called?

Answer 16

MHC restriction

Question 17

MHC are located on what chromosome in humans

Answer 17

chromosome 6

Question 18

how many genes are contained in MHC

Answer 18

more than 200

Question 19

what are MHC called in humans

Answer 19

Human Leukocyte Antigen (HLA genes)

Question 20

where are MHC class I molecules found

Answer 20

1. cell surface of all nucleated cells in vertebrates
2. platelets (no nucleus)

exception: red blood cells

Question 21

where are MHC class II molecules found

Answer 21

on professional antigen-presenting cells important in initiating immune response

(e.g. dentritic cells, mononuclear phagocytes, some endothelial cells, thymic cells, and B cells)

Question 22

because of polygeny of MHC, every person expresses ___ different antigen-presenting MHC class I molecules and ___ MHC class II molecuels on his or her cells

Answer 22

at least 3 MHC class I
3 (or sometimes 4) MHC class II

Question 23

what is the clinical significance of MHC molecules

Answer 23

typically involved in tissue transplatation - donor/host pairs not perfectly matched at HLA locus resulting in graft rejection

Question 24

advances in immunosuppression and improved ability to match donor and host at the genetic level have resulted in a survival rate of ___ of most solid organ grafts ___ years post-transplant

Answer 24

> 80%, 5 years

Question 25

immune response interactions depend on what?

Answer 25

1. cell-to-cell contact 2. mediation by cytokines (secreted proteins)

Question 26

what are cytokines that mediate interactions between leukocytes

Answer 26

interleukins

Question 27

are interleukins soluble proteins

Answer 27

yes

Question 28

what are responsible for controlling the harmful effects of inflammation and tissue-damaging immune reactions (TNF for RA)

Answer 28

inhibiting cytokine

Question 29

majority of cytokines are ___ or ___. rarely are they ___

Answer 29

autocrine or paracrine rarely endocrine

Question 30

B! what type of signal occurs on same cell, adjacent cell, and far away?

Answer 30

autocrine, paracrine, endocrine

Question 31

examples of autocrine hormones/cell signals

Answer 31

growth factors and cytokines

Question 32

examples of paracrine cell signals

Answer 32

hormones and neurotransmitters

Question 33

examples of endocrine cell signals

Answer 33

hypothalamus, pituitary, thyroid, parathyroid, adrenal, pineal body, ovaries, testes

Question 34

what principally produces cytokines of adaptive immunity

Answer 34

CD4+ T cells

Question 35

what is the function of adaptive immunity cytokines

Answer 35

1. promote lymphocyte proliferation and differentiation 2. activate effector cells

Question 36

what are the cytokines of adaptive immunity

Answer 36

IL-2,4,5,7,17 IFN-gamma these are some but there are more

Question 37

what is an abnormal tissue reaction causing tissue injury

Answer 37

hypersensitivity reactions

Question 38

what is the basis of pathology associated with immunologic diseases

Answer 38

hypersensitivity reactions

Question 39

what can elicit HS reactions

Answer 39

exogenous agents or endogenous self antigens

Question 40

dust, pollen, foods, drugs, microbes and various chemicals are examples of what

Answer 40

exogenous agents

Question 41

endogenous self antigens results in ___

Answer 41

autoimmunity

Question 42

what do HS reactions usually result from

Answer 42

1. imbalance between effector mechanism of immune responses 2. control mechanisms that limit these responses

Question 43

HS development is often associated with inheritance of what?

Answer 43

susceptibility genes

Question 44

T/F: mechanism of tissue injury are NOT the same as the effector mechanism of defense against infectious agents

Answer 44

FALSE! they are the same!

Question 45

what type of HS reactions are immune reactant/B cell and what type are cell mediated/T cells

Answer 45

I, II, + III = immune reactant IV = cell mediated

Question 46

what are Type I HS reactions mediated by

Answer 46

antibody IgE and Mast cell

Question 47

what type of antigen for Type I HS

Answer 47

soluble antigen

Question 48

examples of Type I HS

Answer 48

1. allergic rhinitis 2. asthma 3. systemic anaphylaxis

Question 49

explain Type I HS reaction

Answer 49

1. IgE release of antibodies against soluble antigen 2. results in mast cell degranulation

Question 50

what are WBC that play an important role in immune systems response to certain bacterial and parasitic infections

Answer 50

mast cells

Question 51

what do mast cells contain

Answer 51

mainly: histamine also: cytokines, growth factors and heparin

Question 52

where are a majority of mast cells located

Answer 52

skin, lungs, and GI

Question 53

response to antigen in Type I HS occurs in what stages

Answer 53

1. sensitization 2. effect

Question 54

what occurs during sensitization stage of type I HS

Answer 54

host experiences asymptomatic contact w/ antigen

Question 55

what occurs during effect stage of type I HS reaction

Answer 55

pre-sensitized host is reintroduced to antigen which leads to type I reaction (anaphylactic or atopic diseases)

Question 56

clinical syndrome: anaphylaxis (drugs, food, bee sting) what is the clinical and pathologic manifestation?

Answer 56

fall in BP (shock) caused by vascular dilation; airway obstruction due to laryngeal edema

Question 57

clinical syndrome: bronchial asthma what is the clinical and pathologic manifestation?

Answer 57

airway obstruction cause by bronchial smooth ms. hyperactivity; inflammation and tissue injury cause by late-phase reaction

Question 58

clinical syndrome: allergic rhinitis, sinusitis (hay fever) what is the clinical and pathologic manifestation?

Answer 58

increased mucus secretion; inflammation of upper airway, sinuses

Question 59

clinical syndrome: food allergies what is the clinical and pathologic manifestation?

Answer 59

increases peristalsis due to contraction of intestinal muscles