Immunology basics Flashcards

1
Q

Briefly describe what the immune system is.

A

An integrated system of cells and molecules that defends against disease and reacts against infectious pathogens

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2
Q

Name the two arms of the immune system.

A

Innate

Adaptive

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3
Q

Which is more specific, innate or adaptive?

A

Adaptive.

It recognises the specific pathogen and kills it, the innate system just kills any pathogen

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4
Q

Which response is more rapid, innate or adaptive?

A

Innate

Innate develops over hours, adaptive over days/weeks

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5
Q

Which involves the development of immunity, innate or adaptive?

A

Adaptive

Resistance is improved by repeat infections in adaptive.

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6
Q

Which cells are involved in innate immunity?

A

Phagocytes

Natural killer cells

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7
Q

Which cells are involved in adaptive immunity?

A

B and T lymphocytes

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8
Q

What are the soluble factors (found in bloodstream) involved in the innate immune system?

A

Interferons / interleukins

Complement system

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9
Q

What are the soluble factors (found in bloodstream) involved in the adaptive immune system?

A

Antibodies

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10
Q

Describe the difference between the primary and secondary contact with the antigen.

A

Primary contact activates innate and weak adaptive responses

Secondary contact activates enhanced adaptive responses

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11
Q

What are the external barriers to infection?

A

Keratinised skin

Antibiotic secretions: tears

Mucous: GU, GI and respiratory tracts

Low pH: stomach acid

Commensals: good bacteria

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12
Q

What are leucocytes?

A

All white blood cells

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13
Q

What are the two branches of phagocytes?

A

Neutrophils

Mononuclear phagocytes: monocytes & macrophages

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14
Q

What’s the difference between macrophages and monocytes?

A

Macrophages: mononuclear phagocytes that live in tissues

Monocytes: mononuclear phagocytes that live in blood stream

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15
Q

Which are the main phagocytes in the bloodstream?

A

Neutrophils

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16
Q

Which phagocytes live longer?

A

Mononuclear phagocytes

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17
Q

Which phagocytes are more rapid?

A

Neutrophils

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18
Q

What is the main role of neutrophils?

A

Kill pathogens by ingesting them and killing them by releasing toxic contents of their lysosomes, such as H2O2

19
Q

What is the main role of mononuclear phagocytes?

A

Kill pathogens by ingesting them

Also, help initiate adaptive responses

20
Q

How do phagocytes recognise pathogens?

A

They have pathogen-recognition receptors (PRRs)

These recognise pathogen associated molecular patterns (PAMPs)

21
Q

What are PRRs?

A

Pathogen-recognition receptors

Phagocytes have them and use them to recognise pathogens

22
Q

What are PAMPs?

A

Pathogen associated molecular patterns

These are on the pathogen and are recognised by phagocytes

23
Q

Give an example of a PRR and PAMP.

A

On a phagocyte, toll-like receptor (a PRR) recognises a lipopolysaccharides (a PAMP) found on some pathogens

24
Q

What are natural killer cells? And what do they do?

A

Lymphocytes that recognise altered self

They induce apoptosis in virally infected cells and cancer cells

They kill target cells unless they recognise a self protein

25
Q

What’s the name of this cell?

A phagocyte that lives in the bloodstream. It has a short lifespan

A

A neutrophil

26
Q

What’s the name of this cell?

A phagocyte that initiates adaptive immune responses. It lives in body tissue for weeks/months

A

A macrophage

27
Q

What’s the name of this cell?

A phagocytes that initiates adaptive immune responses. It lives in the blood stream and has a long lifespan

A

Monocyte

28
Q

What’s the name of this cell?

It recognises virally infected cells and cancer cells and induces apoptosis.

It also kills any cells on which it can’t recognise a self protein

A

Natural killer cell

29
Q

What is the complement system?

What does it do to help?

A

20 proteins in the blood that get activated when there’s an infection.

They interact to trigger inflammation, cell lysis, phagocytosis

30
Q

What are defensins? And what do they do?

A

Positively charged peptides that are made by neutrophils

They disrupt bacterial membranes

31
Q

What cells produce defensins?

A

Neutrophils

32
Q

What are interferons? What do they do?

A

Proteins

They are produced by virally infected cells

They activate macrophages and NK cells

33
Q

What cells produce interferons?

A

Virally infected cells

34
Q

Where do B lymphocytes mature?

A

Bone marrow

35
Q

Where do T lymphocytes mature?

A

Thymus

36
Q

What is humoral immunity?

A

Immunity involving B cells & antibodies

37
Q

What is cell-mediated immunity?

A

Immunity involving T cells

38
Q

What type of infections does humoral immunity fight?

A

Extracellular bacterial

Secondary viral

39
Q

What type of infections does cell-mediated immunity fight?

A

Viral
Intracellular bacterial
Intracellular parasitic

40
Q

What is the clonal selection theory?

A

We develop with millions of B lymphocytes that are all different, they all recognise different antigens.

The clonal selection hypothesis says: the lymphocytes that recognise ‘self’ are deleted early in development.

41
Q

What is meant by clonal expansion?

A

When a particular B cells encounters its specific antigen, it differentiates rapidly into plasma cells and memory cells.

The plasma cells can then produce the correct antibodies

42
Q

What is primary lymphoid tissue?

A

Where lymphocytes reach maturity

Bone marrow, thymus

43
Q

What is secondary lymphoid tissue?

A

Where mature lymphocytes are stimulated by antigens

Lymph, tissue, blood