Brainscape's Knowledge GenomeTM

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


See full index

Path - Immunology > Immune response to infection > Flashcards

Immune response to infection Flashcards

1
Q

What are the body’s constitutive barriers to infection?

A

External epithelium

Mucous membranes

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

How does the skin stop entry of pathogens?

A
  • tightly packed keratinised cells > physically blocks entry
  • low pH, low O2 tension
  • sebaceous glands (produce oils, lysozyme, ammonia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does mucous stop entry of pathogens?

A
  • acts as physical barrier
  • contains secretory IgA, which binds to pathogens and prevents their entry
  • contains lysozyme
  • contains lactoferrin (starves invading bacteria of iron)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do commensal bacteria stop entry of pathogens?

A

Compete with bacteria for scarce resources

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

What are the components of the innate immune system?

A

Cells

  • PMN cells e.g. neutrophils, basophils, eosinophils;
  • monocytes n macrophages
  • NK cells
  • dendritic cells

Soluble components

  • cytokines, chemokines
  • complement
  • acute phase protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the innate response like in different individuals?

A

It is the SAME in ALL individuals

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

Describe the production and maturation of PMN cells

A

Produced in BM

Migrate to site of injury

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

Describe function of PMN cells

A

Express receptor of cytokines > detect inflamm
Express PRP > detect pathogen
Express Fc receptor for Ig > detect immune complex

Capable of phagocytosis and oxidative/non-ox killing

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

How do macrophages differ from PMN in function?

A

Same

Except they can also process antigens and present them to T cells

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

What re the 5 steps of phagocytic action?

A
  1. Phagocyte recruitment
  2. Recognition of microorganisms
  3. Endocytosis with opsonisation
  4. Formation of phagolysosome
  5. Oxidative killing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens with phagocyte recruitment?

A

Cellular damage triggers production of cytokines and chemokine

  • cytokines enhance permeability of vasc endothelium
  • chemokine attract phagocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens with recognition of microorganisms?

A

PRRs like toll like receptor recognise motifs such as PAMPs > they bind

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

What happens in opsonisation?

A

Opsonins act as a bridge between pathogen and phagocyte’s receptors

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

How is a phagolysosome formed?

A 
Pathogen is uptakes into phagosome 
Phagosome fuses with a lysosome to form a phagolysosome 
Killing of pathogen can occur via: 
- oxidative mechanism
- non-oxidative mechanism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does oxidative killing work?

A

NADPH oxidase converts oxygen into reactive oxygen species, into hydrochlorous acid, which does the killing

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

How does non-oxidative killing work?

A

Release of bactericidal enzymes e.g. lactoferrin, lysozyme

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

What happens after killing of pathogen?

A

Death of the phagocyte > residual enzymes released > liquefaction of adjacent tissue > accumulation of dead/dying neutrophils > pus formation

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

What are the two receptors on NK cells that a normal cell binds to to survive?

A

The activating receptor and the inhibitory receptor

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

What is the receptor on NK cell that a target cell binds to to die?

A

The ACTIVATING receptor only

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

What is the process of maturation for a monocyte?

A

Monocyte produced in bone marrow

To target tissue > becomes macrophage > phagocytosis

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

What are the components of an acquired immune response=?

A 
B lymphocytes (antibodies)
T lymphocytes (CD4, CD8+)
Cytokines, chemokines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a primary lymphoid organ?

A

An organ involved in lymphocyte development

23
Q

What are the 2 primary lymphoid organs?

A 
Bone marrow (both B and T cells produced, only B cells mature here)
Thymus (T cell maturation)
24
Q

What are secondary lymphoid organs?

A

Sites of interaction between naive lymphocytes and microorganisms

  • Spleen
  • Lymph nodes
  • MALT
25
Q

What are the 4 key features of the adaptive immune response?

A
  • Wide repertoire of antigen receptors
  • High specificity
  • Clonal expansion
  • Immunological memory
26
Q

What happens to T cells in the thymus?

A

They undergo +/-ve selection before being exported to the periphery
CD4+ recognises peptides from HLA II
CD8+ recognises peptides from HLA I

27
Q

What affinity must T cells in the thymus display to survive?

A

INTERMEDIATE affinity for HLA
low affinity > they die (FAS triggers apoptosis)
high affinity > they die (auto reactivity)

28
Q

What are CD4+ cells also known as?

A

Helper T cells

Because they HELP development of B cells and of CD8+ T cells

29
Q

What do Th1 Cells produce?

A

INFgamma, TNF alpha and IL2

30
Q

What are T regulatory cells?

A

Subset of lymphocytes that express Foxp3 and CD25

31
Q

What occurs in B cell maturation?

A

They exist in the periphery as IgM B cells

They undergo a germinal centre reaction to differentiate into plasma cells producing IgG, IgE, IgM

32
Q

What is the germinal centre reaction dependent on?

A

CD4+ T helper cells

CD40L:CD40

33
Q

What do B cells undergo after the germinal centre reaction?

A 
Somatic hypermutation 
Isotope switching (from IgM to IgG/E/A)
34
Q

What are immunoglobulins made up of?

A

2 heavy chains, 2 light chains

35
Q

What part of the immunoglobulin determines the antibody class?

A

The heavy chain

36
Q

What part of the antibody recognises the antigen?

A

Fab (antigen binding region), made up of both heavy and light chains

37
Q

What part of the antibody determines the effector function?

A

The constant region of the heavy chain

38
Q

What are the TWO KEY functions of antibodies

A
  • Identification of pathogens (Fab mediated)

- Interaction with other components of the immune response to remove pathogens (Fc mediated)

39
Q

What is the benefit of B cell memory?

A

It decreases the lag time between antigen exposure and antibody production to 2-3 days max

40
Q

What is the function of IgA?

A

Divalent antibody present within mucous

Helps provide a constitutive barrier to infection

41
Q

What are IgM secreting plasma cells?

A

Cells generated rapidly following antigen recognition

Not dependent on CD4 T cell help

42
Q

What are IgG secreting plasma cells dependent on ?

A

dependent on the presence of CD4 T cell help for generation

43
Q

Where is the complement produced?

A

In the liver

44
Q

What is the function of the complement?

A

Produce a rapid highly amplified response

By activating other proteins in a biological cascade

45
Q

What are the three pathways for complement activation?

A

Classical
Mannose Binding Lectin
Alternate

46
Q

What is the classical pathway activated by?

how does it work?

A

By immune complexes

Formation of antibody-antigen immune complex > conformation change in antibody shape&raquo_space; exposes binding side for C1
C1 binding to antibody results in activation of cascade

47
Q

What is the mannose binding lectin (MBL) pathway activated by?

A

DIRECT binding of MBL to microbial cell surface carbohydrates
This stimulates the classical pathway involving C4 and C2 (not C1)

48
Q

How is the alternative pathway activated by?

A

By binding C3 to bacterial cell wall components

49
Q

What factors does the alternate pathway involve?

A

B, I, P

50
Q

How does the complement pathways work

A

C3 triggers the formation of a membrane attack complex via C5-9
This complex makes holes in the membranes

51
Q

What pathways cause cleavage of C3?

A

classical
MBL
alternate

52
Q

What is C9?

A

Part of the final common pathway resulting in generation of the membrane attack complex

53
Q

What are chemokine?

A

Subset of cytokines

They are CHEMOTACTIC - are CHEMOATTRACTANTS

54
Q

list complement functions

A

increase vascular permeability and cell trafficking to sites of inflammation
Opsonisation of immune complexes to keep them soluble
Opsonisation of pathogens to promote phagocytosis
Activation of phagocytes
Promote mast cell/basophil degran
Punches holes in bacterial membranes

Path - Immunology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions