Overview of the immune system Pt 2

Question 1

Timing innate

Answer 1

First line of defence
Fast
Non specific

Question 2

Receptors innate

Answer 2

Use to detect pathogens
Encoded in Germaine
Limited number —> macrophages have same receptors
Unchanging

Question 3

Key cell types innate

Answer 3

Phagocytic cells = macrophages, neutrophils, dendritic cells
And others

Question 4

Actions innate

Answer 4

Induces local inflammtion

Question 5

Responses to repeat infection innate

Answer 5

Same each time

Question 6

Major components innate

Answer 6

Barriers = physical and chemical, like skin
Phagocytes
Some pattern recognition molecules

Question 7

Timing adaptive

Answer 7

Slower to develop = 5-6+ days
About a a week

Question 8

Receptors adaptive

Answer 8

Use randomly generated antigen receptors s
Huge diversity of receptor specificities
Highly specific to individual molecules

Question 9

Key cell types adaptive

Answer 9

Lymphocytes
B AND T CELLS

Question 10

Actions adaptive

Answer 10

Responsible for specific immune response
Most fo times clear infections
Result in memory sometimes

Question 11

Responses to repeat infections adaptive

Answer 11

More rapid and effective With each subsequent exposure
Must be infected by same exact thing each time

Question 12

Major components adaptive

Answer 12

T and B lymphocytes
Antigen specific receptors
Antibodies

Question 13

Phases of immune response - describe

Answer 13

Many phases
Takes time
Innate immune response fast and lasts only days
Adaptive takes longer but lasts longer

Question 14

What does innate immune response start with

Answer 14

Breach of epithelial layer
Body must be exposed to pathogen
Immune cells recognize non self
Macrophages and dendritic cells = sense pattern common amongst pathogens

Question 15

What do immune cells express

Answer 15

Prrs

Question 16

What are prrs

Answer 16

Pattern recognition receptors = provide initial discrimination between self and non self and recognize broad categories of molecules that are commonly found in pathogens = PAMPS
Recognize patterns

Question 17

What are pamps

Answer 17

Pathogen associated molecular patterns
Common foreign structures that characterize whole groups of pathogens = part of many microorganisms but not part of host body’s own cells
Cell wall of bacteria = lipopolysaccharide, rna viruses = double stranded dna, we do not have this in our own body’s

Question 18

What do macrophages express

Answer 18

Several receptors that allow them to recognize diff pathogens = binds many diff pamps

Question 19

What happens when activate prrs axctivated

Answer 19

Now bound = know there is a pathogen, and something must be done
Activate innate immune cells = triggers local inflammation
Activation of prrs on cells like macrophages = directly induce effector functions on these cells = phagocytosis
Cells amplify immune response by producing ifnalmmtiory mediators = cytokines and chemokines

Question 20

What do immune cells induce

Answer 20

Triggers inflammatory response by producing mediators = cytokines and chemokines

Question 21

Hallmarks inflammation

Answer 21

Redness
Heat
Swelling
Pain
Bc all molecules entering and vasodilation

Question 22

Describe whole process inflammtion

Answer 22

Macrophages phagocytosed pathogen = releases cytokines and chemokines
These cells induce inflammatory response and attract cells in circulation = chemokines can bind receptors of blood vessels and cells in circulation
Molecules binding = vasodilation and increased vascular permeability = causes inflammation, immune cells enter site of infection, also fluid enters, lining loser = get hallmarks inflammation

Question 23

What does pathogen detection lead to

Answer 23

Activation of immune cells
Dendritic cells play key role = potent apcs
Detect Pathogens = pamps by receptors = prrs
Leads to dendritic cell activation

Question 24

What links innate to adaptive

Answer 24

Dendritic cells

Question 25

Describe what dendritic cells do

Answer 25

Travel from site of infection to local secondary lymphoid tissue then here interact and activate T cells Once activated = mature by receptor binding Naive to mature dendritic cell = presents antigens, match antigen to cell, recognizes specific T cell = now activated Links innate —>adaptive

Question 26

Describe t and B cell activation

Answer 26

Occurs in lymph node One activated, subset T cells help activate B cells Activated b and T cells - become effector cells = ready to fight

Question 27

How is T cell activated

Answer 27

3 crucial signals APCs activate T cells Happens through 3 signals = need to complete activation, through interaction of specific molecules = receptors and cytokines Happens in peripheral lymphoid tissue =lymph node

Question 28

Name 3 signals that activate T cells

Answer 28

Activation Survival Differentiation

Question 29

Describe basics of antigen presentation

Answer 29

Epitope of antigen can be a specific peptide buried within a protein Antigen/epitope is present using specific molecule = major histocompatibility complex = Mhc= interacts with tcr Only if on mhc, then see if fits receptor

Question 30

Describe activation of adaptive immunity

Answer 30

Antigen specific cells activated in secondary lymphoid tissues= lymph nodes Cells = T cell and B cell

Question 31

What is antigen specificity determined by

Answer 31

Receptors T cell = tcr B cell = bcr, aka antibody aka immunoglobulin

Question 32

Describe antibodies

Answer 32

Secreted immunoglobulin molecules Made by b lymphocytes and it’s progeny plasma cells Binds antigens Present in serum = fluid component of blood, circulating

Question 33

Do all antibodies reognize the same epitopes

Answer 33

2 antibodies can recognize diff epitopes on same antigen Bc so very specific

Question 34

Describe difference in b and T cells = origin/maturation

Answer 34

B cells arise and mature in bone marrow T cells arise from bone marrow progenitors but are generated and mature in thymus

Question 35

Describe difference in b and T cells = receptors

Answer 35

Bcr can be membrane bound or secreted (antibodies) Tcr only exits as membrane bound

Question 36

Describe difference in b and T cells = recognition

Answer 36

Tcr can only recognize small pieces of antigen bound to molecules of MHC on the surface of apcs Bcr can recognize ag in natural form = do not need to be processed by dendritic and presented on mhc

Question 37

Describe specificity of bcr and tcr - gen

Answer 37

Individual b and T cells each have individual specificity for a single antigen Each lymphocyte expresses many identical copies of one receptor with specificity for one antigen Huge diversity of lymphocytes = each with own specificity Theoretical potential to response to any antigen that may come along

Question 38

Describe specificity of bcr and tcr - how

Answer 38

Accomplished by rearranging and editing genomic dna that encodes the antigen receptors expressed by each b and T cell = creates diversity

Question 39

What happens during dev

Answer 39

If lymphocyte reacts to self antigen = eliminated Self reactive cells removed Do not want autoreactive lymphocytes

Question 40

Describe clonal selection

Answer 40

When b or T cell interact with its specific antigen = selected and becomes activated Activation results in prolife = produces large number of clones,= each reactive against antigen that initially stimulated original lymphocyte= differentiation Now becomes effector cell = mature now

Question 41

What happens when egress to site of infection

Answer 41

Effector cells now —> once t and B cells are activated in lymphoid organs = becomes effector cells that can fight infections Happens through both humoral and cell mediated activities —> then leave lymph node to site of infection

Question 42

What does humoral immunity use

Answer 42

Combats pathogens via antibodies

Question 43

What does cell mediated immunity involve

Answer 43

Primarily T lymphocytes

Question 44

Describe cell mediated immunity

Answer 44

Mediated by T cells Contribute to adaptive immunity in many ways Many diff T cell subsets can get activated depending on the situation and exert a variety of effector functions

Question 45

Describe cell mediated immunity - general effector functions

Answer 45

Some help activate B cells = follicular t helper cell, role = actiavte B cell Some help activate macrophages = boost activity Some kill infected cells directly = cytotoxic

Question 46

Describe humoral immunity

Answer 46

Mediated by antibodies produced by B cells Contribute to adaptive immunity by producing specific antibodies Antibodies = diff types, act in diff ways, involved in clearing and/or neutralizing antigen Covers pathogen so cannot bing to something else and replicate, help macrophages or phagocytic cells phagocytose

Question 47

Describe regulation and memory

Answer 47

Hopefully after infection = downregulation of lymphocytes and immunological memory

Question 48

What is immunization

Answer 48

Deliberate induction of an adaptive immune response

Question 49

Describe active immunization

Answer 49

Natural = natural infection Induced = vaccination

Question 50

Describe passive immunization

Answer 50

With cells and/or molecules that mediate immunity Natural = mother to fetus transfer of antibodies Induced = monoclonal antibody therapy