Innate Immunity

Question 1

Name some features of innate immunity?

Answer 1

-“inbuilt”, present from birth -not enhanced by second exposure (has no memory) -Uses cellular and soluble components Rapid response,minutes to hours, cooperates with and directs adaptive immunity

Question 2

Recall the physical barriers used by the immune system in host defence?

Answer 2

Anatomical(physical) Skin-mechanical barrier, acidic environment Mucous membranes- mucus secretions trap microorganisms, cilia expel microorganisms

Question 3

Recall the chemical (physiological) barriers used by the immune system in host defence?

Answer 3

-Body temperature/fever -Low pH- acidic pH of stomach kills many ingested microorganisms -Chemical mediators-lysozyme, interferons,complement

Question 4

What does inflammation do?

Answer 4

local vascular permeability increases

Question 5

Name the different tyoes of innate immunity defensive barriers?

Answer 5

Anatomical(physical) Physiological Phagocytic Inflammatory

Question 6

Name the different cell types of the immune system?

Answer 6

Nuetrophil Eosinophil Dendritic cell Mononcyte/macrophage Basophil Mast cell Natural killer cell Never Ever Did My Baby Meet Norman

Question 7

Name the function and mechanism of Neutrophils?

Answer 7

Phagocytosis and killing microbes

Question 8

Name the function and mechanism of Eosinophil?

Answer 8

Phagocytosis,granule release, defence against parasitic infections and help B cell responses in GALT (IgA production) and involved in allergies

Question 9

Name the function and mechanism of Basophils?

Answer 9

Granule release, may act as APC for “type 2 immunity” also involved in allergies and the release of histamine (hay fever)

Question 10

Name the function and mechanism of monocyte/macrophages?

Answer 10

Phogocytosis,killing, cytokine release act as APC (antigen presenting cell)

Question 11

Name the function and mechanism of Mast Cells?

Answer 11

Granule release (pro- inflammatory)

Question 12

Name the function and mechanism Dendritic cell?

Answer 12

Antigen capture and presentation

Question 13

Name the function and mechanism of Natural killer cells?

Answer 13

Lysis of infected cells

Question 14

Name major features of nuetrophils?

Answer 14

(polymorphonuclear leukocyte) 40-75% of leukocytes; short lived cells, circulate in blood then migrate into tissues; first cells to be recruited to a site of tissue damage/infection

Question 15

Name the major features of macrophages?

Answer 15

less abundant, dispersed throughout the tissues; signal infection by release of soluble mediators

Question 16

To fight infection neutrophils need to….

Answer 16

1. move from circulation into tissues to site of infection 2. bind pathogen 3. phagocytose pathogen 4. kill pathogen

Question 17

What is opsonisation?

Answer 17

opson = greek for a sauce or relish coating of micro-organisms with proteins to facilitate phagocytosis opsonins are molecules that bind to antigen, and also can be bound by phagocytes antibody and complement function as opsonins

Question 18

Name some oxygen-independent killing mechanisms for nuetrophils?

Answer 18

enzymes lysozyme hydrolytic enzymes antimicrobial peptides (defensins)

Question 19

Name some oxygen-dependent killing mechanisms for nuetrophils?

Answer 19

respiratory burst: superoxide anion hydrogen peroxide singlet oxygen hydroxyl radical reactive nitrogen intermediates nitric oxide

Question 20

How can nuetrophils form Neutrophil Extracellular Traps?

Answer 20

Activated neutrophils release granule proteins and chromatin to form extracellular fibres

Question 21

What do mast cells release?

Answer 21

Secrete histamine and other inflammatory mediators, including cytokines

Question 22

What can activate Mast cells?

Answer 22

Question 23

What do Mast cells Lead to?

Answer 23

Leads to vasodilation and increased vascular permeability

Question 24

Can Mast cells recognise, Phagocytose and kill Bacteria?

Answer 24

Yes

Question 25

What are Natural Killers cells important for?

Answer 25

Important in defence against tumour cells and viral infections (esp.herpes)

Question 26

Are natural killer cells Large granular lymphocytes?

Answer 26

yes

Question 27

What do the recptors of natural killer cells bind to?

Answer 27

The receptors bind to antibody-coated cells (Antibody Dependent Cell-mediated Cytotoxicity)

Question 28

Natural killer cells have antigen-specific receptors and express both activating and inhibatory receptors: balance of signals?

Answer 28

First part false and second part true.

Question 29

What are cytokines?

Answer 29

-Small secreted proteins -Cell-to-cell communication -"messengers" of the immune system -Generally act locally -Biological effects at very low concentrations -short-lived So Many So Called Money Bombs

Question 30

Name the different types of cytokines?

Answer 30

interleukins (IL-x): between leukocytes interferons (IFN): anti-viral effects chemokines chemotaxis, movement growth factors cytotoxic tumor necrosis factor (TNF)

Question 31

What do chemokines do?

Answer 31

They are required for chemotaxis and recruitment of cells to particular sites

Question 32

What are growth factors required for?

Answer 32

growth factors are required for the development of cells in the immune system

Question 33

What type of effects do interferons have?

Answer 33

Have anti-viral effects

Question 34

What do cytotoxic cytokines do?

Answer 34

They can induce cell death: tumour necrosis factor

Question 35

Where are dendritic cells located?

Answer 35

near the skin and mucosal epithelia

Question 36

Dendritic cells do not secrete pathogens?true or false

Answer 36

false dendritic cells secrete cytokines

Question 37

How do dendritic cells work in the immune system and where do they migrate to ?

Answer 37

-Recognise and engulf pathogens -Migrate to lymph nodes to present antigens to the adaptive immune systems

Question 38

What does the complement system lead to?

Answer 38

Question 39

What is the complement system?

Answer 39

A complex series of proteins in serum and in tissues which form a triggered enzyme cascade system, leading to opsonisation of micro-organisms, direct killing of microorganisms, promotion of inflammation and recruitment of luekocytes

Question 40

What major role does the complement system play?

Answer 40

Plays a major role in complementing the activity of specific antibody.

Question 41

What does the complement system cause that leads to the opsonisation of microorganisms?

Answer 41

Triggered enzyme cascade system

Question 42

Name some features of the complement system?

Answer 42

Plays a major role in complementing the activity of specific antibody complex series of ~30 proteins and glycoproteins, total serum conc. 3-4 mg/ml triggered enzyme cascade system rapid, highly amplified response components produced mainly in the liver, but also by monocytes and macrophages

Question 43

Name the three pathways of complement activation?

Answer 43

The Classical Pathway The Alternative Pathwway The Lectin Pathway

Question 44

Describe the triggered enzyme cascade system?

Answer 44

-Components are present in the body as inactive enzyme precursors -initial event is rapidly amplified -To become activated a protein has to have a part of it cleaved- this makes it an activated enzyme -This enzyme then cleaves of a part of another protein making it an activated enzyme. (because it is an enzyme it can cleave multiple protiens) -They go on and cleave of another part of another protein

Question 45

Name the pathways that activate that triggered enzyme cascade?

Answer 45

The Classical Pathway initiated by antigen-antibody complexes The Alternative Pathway direct activation by pathogen surfaces The Lectin Pathway antibody-independent activation of Classical Pathway by lectins which bind to carbohydrates only found on pathogens

Question 46

What is the classical pathway?

Answer 46

The antibody binds to the antigen causing the enzyme cascade system

Question 47

When is the alternative pathway activated?

Answer 47

Direct activation by pathogen surfaces involves complementary binding to the microbial surfaces doesn't require antibodies

Question 48

What is the Lectin Pathway?

Answer 48

antibody-independent activation of Classical Pathway by lectins which bind to carbohydrates only found on pathogens

Question 49

What are lectins?

Answer 49

protein that can bind to carbohydrates only found in pathogens

Question 50

Draw the complement activation pathway/

Answer 50

On the ppt slide

Question 51

Name the functions of the Complement?

Answer 51

Lysis Opsonization Activation of inflammatory response Clearence of immune complexes

Question 52

Local inflammatory response may be accompanied by a systemic response "acute phase" after how many days?

Answer 52

1-2 Days

Question 53

What induces a systemic "acute-phase" response?

Answer 53

Cytokines

Question 54

What symptoms are present in an acute-phase response?

Answer 54

Fever

Question 55

Where are acute-phase proteins produced?

Answer 55

Liver

Question 56

What protein is measured clinically as a marker of inflammation?

Answer 56

C-reactive Protein CRP

Question 57

Name the four acute phase proteins?

Answer 57

C-Reacctive protein -Activates Complement Mannan binding Lectin(MBL)-activates complement complement fibrinogen(clotting)

Question 58

What is the end result of a complement cascade ?

Answer 58

lysis opsonization Activation of inflammatory response clerance of immune complexes

Question 59

Draw a diagram showing the complement activation pathways ?

Answer 59

add pic

Question 60

What does the MAC form and how does it kill pathogens?

Answer 60

The membrane-attack complex (MAC) forms transmembrane channels. These channels disrupt the cell membrane of target cells, leading to cell lysis and death.

Question 61

what is the complement system?

Answer 61

complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's plasma membrane. It is part of the innate immune system

Question 62

Explain the principle of activating and inhibatory cell surface receptors for NK cells

Answer 62

Question 63

Why are NK cells a part of the innate immune response?

Answer 63

Typically, immune cells detect major histocompatibility complex (MHC) presented on infected cell surfaces, triggering cytokine release, causing lysis or apoptosis. NK cells are unique, however, as they have the ability to recognize stressed cells in the absence of antibodies and MHC, allowing for a much faster immune reaction. They were named "natural killers" because of the initial notion that they do not require activation to kill cells that are missing "self" markers of MHC class 1.[1]This role is especially important because harmful cells that are missing MHC I markers cannot be detected and destroyed by other immune cells, such as T lymphocyte cells. They lack an antigen specific receptor

Question 65

What is an acute phase response?

Answer 65

It is a systemic inflammatory response caused by injury or infection. In response to the injury local inflammatory cells (nuetrophils and macrophages) release many cytokines ( interleukins IL1, IL6 and IL8, and TNFα.). These cytokines cause a fever and causes the liver to produce many acute phase proteins ( C-reactive protein, mannose-binding protein, complement factors, Serum A) These acute phase proteins help fight infection by optimization and trapping of microorganism and their products, in activating the complement system, in binding .

Question 66

Define MHC haplotype?

Answer 66

Haplotype is a group of MHC molecules linked to one chromosomes. Different MHC haplotypes lead to differnt immune responses. This definition of haplotype applies whether it is just a few genes or all of the genes on an entire chromosome11. In the case of the major histocompatibility complex, it is a group of more than 200 genes on chromosome 6 (Janeway et al. 2001). The set of alleles11 inherited together from one parent form the MHC haplotype. Thus, one offspring will inherit two different MHC haplotypes, one from each parent. The different haplotypes with so many genes helps keep genetic variation in the overall complex, which improves the immune response ability of the organism.