Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MIIM30002 > Lecture 8: Adaptive Immunity and Immune Recognition > Flashcards

Lecture 8: Adaptive Immunity and Immune Recognition Flashcards

1
Q

What are the general features of adaptive immunity?

A

evolutionarily relatively new
slow, but highly specific response directed against antigen
forms immunological memory = results in a rapid 2˚ response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the soluble factors of adaptive immunity?

A

antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the cell-associated factors of adaptive immunity?

A

B cell receptors, T cell receptors and MHC molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the specialised cells of adaptive immunity?

A 
B cells (B1/B2)
T cells (Th1, Th2, Th17, Tfh, Th17, Treg and cytotoxic T cells)
semi-invariant T cells (NKT, MAIT), ɣσ T cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the priming phase of adaptive immunity?

A

first time the adaptive immune system encounters an antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the effector phase of adaptive immunity?

A

activated adaptive cells differentiate into effector cells to fight infection and eliminate pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the contraction phase of adaptive immunity?

A

most effector cells die following clearance of the pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the memory phase of adaptive immunity?

A

some long lived memory cells remain to ensure that the immune system can respond faster and stronger upon re- encountering that pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What makes adaptive immunity highly specific?

A

highly diverse antigenic receptors formed by random gene rearrangement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What makes adaptive immunity respond slower?

A

this is because major effector functions include antibody production, cytokine secretion and cytotoxicity, some of which take days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the outcome of the adaptive immune response?

A

removal/neutralisation of the pathogen and resolution of infection and memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What ability does memory grant the adaptive immune system?

A

the ability to respond stronger and faster on second encounter of the same pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which lineage comprises cells of the adaptive immune system?

A

the lymphoid lineage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are B cells derived from and where do they mature?

A

from lymphoid progenitor

mature in bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How many BCRs does each B cell have?

A

around 100,000 each with the same specificity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does BCR engagement lead to?

A

proliferation and transition into plasma cells (‘effector B cells’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do plasma cells secrete?

A

soluble BCR (= antibodies) that have same specificity as surface receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is humoral immunity?

A

B cell-mediated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are T cells derived from and where do they mature?

A

from lymphoid progenitor in bone marrow

develop and become educated in the thymus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What co-receptors do T cells express?

A

either CD4 (MHC class II restricted) or CD8 (MHC class I restricted)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do T cells recognise antigens?

A

via distinct cell surface receptors (α/β T cell receptor) with high degree of specificity
requires processing of antigen by the APC and presentation on MHC

22
Q

What happens after T cells are activated?

A

they can leave the blood and survey the periphery: accumulating where they are needed

23
Q

What is the role of CD4+ Helper T cells?

A

regulators of immune responses

24
Q

What is the role of CD8+ Cytotoxic T cells?

A

cytotoxic (perforin, granzymes)

25
Q

What is cell-mediated immunity?

A

T cell-mediated

26
Q

What determines whether a naive CD4+ T cell will become a Tfh, Th2, Th1, Th17 or iTreg?

A

the cytokines released during activation

27
Q

What does each lymphocyte carry?

A

a single and unique specificity for antigen

28
Q

What does diversity in lymphocyte specificity provide us with?

A

the greatest opportunity to fight infections throughout our lifetime - therefore it is important to remember that these cells are present (in low numbers) prior to an infection

29
Q

How does clonal expansion occur?

A

at first there are multiple lymphocytes clones with different specificities -> deletion of self-reactive clones (clonal deletion) -> clonal selection -> clonal expansion

30
Q

When it’s a one in a million chance, how does one lonely antigen-specific lymphocyte meet its perfect antigenic match?

A

‘speed dating’ in specialised
areas/hubs in secondary lymphoid organs
anatomical structure makes the impossible a reality

31
Q

What are the rules of lymphocyte engagement?

A

naïve lymphocytes recirculate through lymph node/spleen via blood
antigens/pathogens are funnelled from the periphery into the local lymph nodes

32
Q

How do naïve lymphocytes recirculate through lymph node/spleen via blood?

A

enter lymph node via blood vessels: lymphocytes squeeze through the walls of specialised blood vessels

33
Q

How are antigens/pathogens funnelled from the periphery into the local lymph nodes?

A 
extracellular fluid (lymph) flows from peripheral tissue and is collected by lymphatic vessels and delivered to the draining lymph node
activated dendritic cells migrate to lymph node and presents antigen to T cells
34
Q

What are the features of antigens?

A

can be simple or complex

any substance that may be specifically bound by immunoglobulin or T cell receptor

35
Q

What is an epitope?

A

an antigenic determinant
part of the antigen that is recognised
each lymphocyte is specific for one epitope

36
Q

What is an immunogen?

A

substance that induces a specific immune response

all immunogens are antigens

37
Q

Which factors affect immunogenicity?

A

foreignness, high MW, chemical complexity, degradability and also genetic variation of individual, dosage of immunogen, route of administration

38
Q

Are most proteins strongly immunogenic?

A

yes and protein carriers can increase immunogenicity of other molecules

39
Q

What are haptens?

A

small organic moiety attachable to larger structure
target of antibody response (contains Ab determinant)
non-immunogenic

40
Q

What are carriers?

A

usually protein or polypeptide (e.g. ovalbumin)
required for adaptive immune response
minimum size required to cross-link surface BCRs
contains T cell determinants

41
Q

In order to generate an antibody response to the hapten, what must hapten? lol

A

hapten must be covalently linked to the carrier

42
Q

How many molecules does the innate immune system recognise vs the adaptive immune system?

A

innate: ~1000
adaptive: >10^7

43
Q

How many types of receptors are there in the innate immune system vs the adaptive immune system?

A

innate: <100 types, each invariant
adaptive: 2 types (Ig, TCR)

44
Q

How are receptors distributed in the innate immune system vs the adaptive immune system?

A

innate: non-clonal
adaptive: clonal

45
Q

How would receptors be expressed within a population of lymphocytes before encountering an antigen?

A

single unique receptors would be expressed on each lymphocyte

46
Q

How do T cell receptors recognise antigen?

A

in the form of a complex of a foreign peptide bound to an MHC molecule

47
Q

What must happen in order for peptides to be presented?

A

must be processed

48
Q

What is required to make an effective response to the peptide antigen?

A

the CD4 and CD8 cell-surface proteins of T cells must directly contact MHC molecules

49
Q

What can immunoglobulins recognise?

A

all manner of shapes and chemical compositions because they are highly specific, discriminating between small differences in protein sequences and chemical compositions

50
Q

The majority (~90%) of B-cell receptor epitopes are what?

A

conformational (discontinuous)

51
Q

How do immunoglobulins bind to antigens?

A

bind to conformational shapes on the surfaces of antigens using a variety of non-covalent forces
also influenced by steric constraints

MIIM30002 (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions