BIOL 435 Ch. 1 (Overview of the Immune System)

Question 1

immunity

Answer 1

-state of protection against foreign pathogens or substances (antigens)
>sometimes not foreign (ex. cancer)
-“exempt”

Question 2

observations of immunity

Answer 2

• go back over 2000 years

- noticed that those recovered from the plague could safely nurse the currently ill

Question 3

vaccination

Answer 3

• prepares the immune system to eradicate on infectious agent before it causes disease
• widespread use has saved many lives
  ex. rabies vaccination and eradication of small pox

Question 4

Louis Pasteur

Answer 4

• ‘old’ (attenuated) bacteria into chickens and didn’t die

- could inoculate and prevent disease

Question 5

virulation

Answer 5

• dried puss into cuts

- became immune by getting a milder case

Question 6

attenuation

Answer 6

-weakened strength or ability to cause disease

Question 7

immune system components

Answer 7

1. Innate
2. Adaptive
   * don’t work independently

Question 8

innate immunity

Answer 8

-very fast (minutes to hours)
-limited and fixed
-same response each time
Major components:
-barriers (eg. skin)
-phagocytes
-pattern recognition molecules
-can work independently

Question 9

adaptive immunity

Answer 9

-slower response
-highly diverse and adapts
-different response each time (more rapid and effective)
-can’t work independently
-not in everyone
Major components:
-T and B lymphocytes
-antigen-specific receptors
-antibodies (Ab)

Question 10

cooperatively

Answer 10

• innate and adaptive immunity
• activation of innate(+adaptive) produces signal molecules (cytokines and chemokines:’trail of bread crumbs’)
• these molecules stimulate and direct adaptive immune responses

Question 11

innate immune responses

Answer 11

-first line of defence
>fast, relatively nonspecific
-uses germ-line encoded (inherited) pattern recognition receptors (PRR)
-also uses phagocytic cells

Question 12

PRR

Answer 12

• pattern recognition receptors
• bind to PAMPs
• target something that will always be on pathogens

Question 13

PAMPs

Answer 13

• pathogen-associated molecular patterns
• generic molecules found on many different types of pathogens
• eg. peptidoglycan

Question 14

adaptive immune responses

Answer 14

1. Humoral responses (B-cells)
2. Cell-mediated responses (T-cells)
   - slower to develop (5-6days)
   - use randomly generated antigen receptors
   - highly specified to individual antigen molecules

Question 15

randomly generated antigen receptors

Answer 15

-these bind to very specific antigens, rather than molecules found on many pathogens
>ex. bind to a single component of peptidoglycan

Question 16

memory

Answer 16

• the hallmark of adaptive immunity

- NOT present in innate immunity

Question 17

primary response (memory)

Answer 17

• initiated upon first exposure to an antigen

- memory lymphocytes are left behind after antigen is cleared

Question 18

secondary response (memory)

Answer 18

• initiated upon second exposure to the same antigen that stimulates memory lymphocytes
• stimulation yields faster, more significant, better adaptive response

Question 19

humoral immunity

Answer 19

• combats pathogens via antibodies (Ab)
• Ab produced by B-lymphocytes
• Ab can be transferred between individuals to provide passive immunity

Question 20

cell-mediated immunity

Answer 20

-involves primarily T lymphocytes

>can eradicate pathogens, clear infected self-cells or aid other cells in inducing immunity

Question 21

surface receptors

Answer 21

• used in humoral and cell-mediated immunity
• B-cell receptors (BCR)
• T-cell receptors (TCR)
• randomly generated by gene segment rearrangements in B and T cells (rearranging the DNA)
• once released from membrane=Ab

Question 22

B-cells encounter antigen

Answer 22

-produce antibodies matching the specificity of their BCR

>cell membrane immunoglobin

Question 23

T-cell receptors

Answer 23

-bind specific peptides displayed on the surface of other cells
>peptides must be bound to special presentation molecules called MHC (self) and peptide (non-self)
-positive and negative selection

Question 24

individual B and T cells

Answer 24

• have an individual specificity for a single antigen

- due to having many copies of a receptor on their surface that only binds to one type of antigen

Question 25

B- and T-cell interacts with unique antigen

Answer 25

-it is selected and becomes activated | >results in a proliferation (producing a large number of clones)

Question 26

each clone

Answer 26

- reactive against the same antigen that initially stimulated the original lymphocyte - each produces antibodies and releases them to fight the pathogen

Question 27

4 major categories of pathogens

Answer 27

-viruses -bacteria -fungi -parasites *immune responses are quickly tailored to the type of organism involved >depends on structure of pathogen and location

Question 28

SARS-CoV-2

Answer 28

-severe acute respiratory syndrome coronavirus 2

Question 29

tolerance

Answer 29

- ensures that the immune system avoids destroying host tissue - helps keep anti-self recognition molecules (due to random rearrangement) from circulating in bloodstream

Question 30

negative selection process

Answer 30

- cells too reactive to 'self' are culled | - important that it works, otherwise we get auto-immunity

Question 31

tolerance mechanisms

Answer 31

- any cells or receptors that respond to self are eliminated - host should always know difference between self and non-self - danger/damage vs. safe (not as much self vs. non-self)

Question 32

dysfunctions of immunity categories

Answer 32

1. Overly active | 2. Immunodeficiency

Question 33

overly active

Answer 33

- or misdirected immune response - allergies - asthma - autoimmune disease (eg. MS, Crohn's)

Question 34

immunodeficiency

Answer 34

- primary loss of immune function (genetic) | - secondary loss of immune function (acquired)

Question 35

secondary (acquired) loss of immune function

Answer 35

- opportunistic infections can occur in people with impaired immune responses ex. oral thrush and HIV

Question 36

transplanted tissues

Answer 36

- a rare case where we want to AVOID an immune response - don't want rejection - body's natural response to foreign tissue is to attack it and destroy it

Question 37

cancer

Answer 37

- situation where the dangerous cells we want to target are our own self-cells - generally tolerated and hard to generate immunity against

Question 38

the microbiome

Answer 38

- community of commensal organisms that live in and on us the cause no harm - function in homeostasis (metabolic and immune balance)

Question 39

imbalance or dysbiosis

Answer 39

- leads to immune overstimulation resulting in inflammation | - due to dietary changes or environmental factors (ex. stress)

Question 40

inflammation

Answer 40

``` -cause of many things >CVD >diabetes >obesity >allergies ```

Question 41

symbiosis

Answer 41

-gut barrier integrity -gut-brain-immune homeostasis >balanced immune function >neurologic homeostasis >metabolic regulation

Question 42

antigen (Ag)

Answer 42

- any molecule that will specifically stimulate B- and T- cells and produce an adaptive immune response - general: anything that produces an immune response

Question 43

humoral

Answer 43

-blood borne

Question 44

passive immunity

Answer 44

- not very long - not as good as active immunity ex. injecting antibodies into a human to treat a snake bite