Lecture 9 - Adaptive Immune Response (Recognition) Flashcards

1
Q

What does the suffix -mab mean?

A

Monoclonal antibody

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2
Q

What is a pathogen?

A

Any microorganisms that can cause disease in humans?

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3
Q

What is a Naive T cell?

A

T cells that have not yet encountered the antigen of a pathogen

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4
Q

What is the only cell that can activate T cells?

A

APCs (Antigen presenting cells)

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5
Q

How do APCs give information to T cells?

A

Sense the pathogen
Capture the pathogen
Process the pathogen
Present the pathogens antigen to T cells

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6
Q

What are the 4 different APCs?

A

Dendritic cells
Langerhans cells
Macrophages
B cells

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7
Q

What is the similarity between Dendritic cells and Langerhans cells?

A

Langerhans are just Dendritic cells that are present in the skin

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8
Q

What do dendritic cells and langerhans cells present antigens/pathogens to?

A

Naive T cells

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9
Q

What cells do Macrophages and B cells present pathogens/antigens to?

A

Effector T cells

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10
Q

What is the function of Dendritic cells and langerhans cells presenting pathogens to Naive T cells?

A

To stimulate T cell response against most pathogens

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11
Q

What is the T cell response?

A

T helper cells (help B cells)
Cytotoxic T cells

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12
Q

What is the function of Macrophages presenting pathogens to Effector T cells?

A

Produce cytokines which promotes phagocytise activities

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13
Q

What is the function of B cells presenting pathogens to effector (helper) T cells?

A

To stimulate the Antibody response (Humoral response)
Aim to produce the best antibody IgG

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14
Q

What are effector T cells?

A

T cells that have previously encountered the antigen and are capable of performing effector functions during an immune response

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15
Q

What is the largest lymphoid organ in the body?

A

Spleen

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16
Q

What are the 3 key features of APCs?

A

Strategic location

Diversity in pathogen capture mechanism (Phagocytosis + macropinocytosis)

Diversity in pathogen sensors (PRRs)

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17
Q

What do the PRRs of APCs bind to on pathogens?

A

PAMPs

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18
Q

What type of receptors are often PRRs to detect pathogens?

A

Toll like receptors

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19
Q

Where can toll like receptors be found?

A

On plasma membrane of the cell (extracellular pathogen detection)

Nuclear membrane (intracellular pathogen detection)

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20
Q

What toll like receptor typically binds to Staphylococcus aureus?

A

TLR2
Since it’s Gram +ve

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21
Q

What pathogen associated molecules bind to TLR4?

A

Lipopolysaccharides
E.g made by Neisseria meningitidis or E.coli
Gram Negative

22
Q

What does binding of endotoxins (Lipopolysaccharides) to TLR4 activate?

A

Innate immunity
Inflammatory response

23
Q

What happens to the APCs once its captured and processed the pathogen?

A

Migrates to lymphoid tissue to activate the maximum amount of T and B cells as possible

24
Q

What are a few examples of lymphoid tissues?

A

GALT (In Gut)
BALT (In Bronchioles of lungs)
SALT (In Skin)

Lymph nodes
Spleen

25
Q

What happens to the APCs once they’ve migrated to the lymphoid tissue?

A

Present antigens to correct T cells that lead to the best adaptive immune response

26
Q

What adaptive immune response is stimulated when exposed to extracellular microbes?

A

Humoral Immunity (Antibody production)

27
Q

What adaptive immune response is stimulated when exposed to intracellular microbes?

A

Cell mediated immunity (Cytotoxic T cell response)

28
Q

What is the function of Cytotoxic T cells?

A

Destroys infected cells
(E.g cells infected by a virus)

29
Q

What do Intracellular microbes usually produce that stimulate natural killer cells?

A

Interferons

30
Q

What is the importance of APCs?

A

In infection by Intracellular or extracellular they present pathogens to Naive T cells activating the best immune response (Humoral immunity or cell mediated immunity)

31
Q

How are pathogens presented to naive T cells?

A

Via MHCs (Major Histocompatibility Complex) also called HLA (Human Leukocyte Antigen)

MHC = HLA

32
Q

What are the 2 types of MHC molecules?

A

MHC Class I
MCH Class II

33
Q

What cells express MHC Class I molecules?

A

ALL Nucleated cells

34
Q

What cells express MHC Class II molecules?

A

Antigen-presenting cells (Dendritic cells, macrophages and B cells)

35
Q

What class of MHC molecules do Dendritic cells have?

A

Both MHC Class I and Class II

Is both a nucleated cell and an antigen presenting cell

36
Q

What class of MHC molecules do red blood cells have?

A

Neither since they are not nucleated (no Class I) or Antigen presenting cells (no Class II)

37
Q

What type of microbes, (intracellular or extracellular) are always presented by MHC Class I molecules?

A

Intracellular microbes

38
Q

What type of microbes, (intracellular or extracellular) are always presented by MHC Class II molecules?

A

Extracellular microbes

39
Q

What is the advantage of their being different alleles for MHC molecule production?

A

Means different people can respond to different microbes

40
Q

What T cells will recognise MHC Class I molecules?

A

CD8 positive T cells

41
Q

What T cells will recognise MHC Class II molecules?

A

CD4 positive T cells

42
Q

When invaded by extracellular microbes, what class of MHC molecule on the APC presents it to the Naive T cell?
What molecules will these T cells have?

A

MHC Class II
CD4 positive Naive T cells

43
Q

When invaded by intracellular microbes, what class of MHC molecule on the APC presents it to the Naive T cell?
What molecules will these T cells have?

A

MHC Class I molecules
CD8 positive Naive T cells

44
Q

What Naive T cells are responsible for triggering Cell-mediated/cytotoxic T cell response?

A

CD8+ T cells

45
Q

What is the exogenous pathway/processing of extracellular microbes?

A

Microbes captured via phagocytosis or macropiniocytosis
Degraded in endosome
Vesicle containing MHC Class II complex fuses witht endosome
APCs present these antigens to CD4+ T cells

46
Q

What is the endogenous pathway/processing of intracellular microbes?

A

Viral protein in the cytosol
Proteasome marks it for destruction
Broken down antigenic peptide transported to the ER
Peptide exposed to MHC Class I
Complex displays the viral antigen to CD8+ T cells

47
Q

Why is it good that there is genetic polymorphism for MHC molecules?

A

No 2 individuals have same set of MHC molecules so a single microbe is unlikely to wipe everybody out

More diversity of MHC molecules means more likely to develop immunity to a disease

48
Q

If a patient with HIV has low CD4+ T cell count and a high viral load, what treatment would you do?

A

Anti-retro viral Therapy

49
Q

If a patient with HIV had a High CD4+ T cell count and a low viral load, what would you do?

A

Nothing

50
Q

Why is it important that the HLA molecules (MHC) between an organ donor and recipient match?

A

Rejection

51
Q

What autoimmune diseases are associated with the presence of certain HLA molecules?

A

Ankylosis spondylitis
Insuli-dependant Diabetes Mellitus
SLE (Systemic Lupus Erythromatosus)

52
Q

Is a patient more or less susceptible to suffering to an infection if they have a low MHC molecule diversity?

A

More susceptible