Immunology

Question 1

How can we split the immune response?

What makes up each of these categories?

Answer 1

Innate

• Physical barriers
• Physiological barriers
• Commensal bacteria
• Mucous
• Sebaceous secretions

Adaptive

• Humoral B cells
• Cell-mediated T cells

Question 2

Compare innate and adaptive immunity in terms of…

Time?
Specificity?
How it works?
Memory?

Answer 2

Rapid (minutes and hours) vs. slow (days and weeks)

No memory vs. immunological memory (from memory B cells)

Non-specific vs. specific for each type of antigen

PAMPS + PRR vs. antigens and antibodies

Question 3

What does a high neutrophil count mean?

Are neutrophils long or short lived?

Answer 3

• raised neutrophils = ACUTE inflam

- short-lived

Question 4

Dendritic cells

• describe their role in immunology

Answer 4

Antigen presenting cells (APC) - present antigens from phagocytosis via MCH class II to CD4 cells

Bridge gap between innate and adaptive

Question 5

Mast cells

Answer 5

Allergic response

Release histamine and heparin = kill by degranulation

Question 6

Define opsonisation

Answer 6

Coating of pathogens by soluble factors to enhance phagocytosis

E.g. C3b and Ig

Question 7

Draw Complement system

What is C3 and MBL an example of? What of these is used prognostically?

Answer 7

Compare to diagram in onenote

Acute phase protein - CRP is used to measure acute inflam (v. short half life so disappears v quickly after inflam dies down)

Question 8

What 3 ways can complement system be activated?

Answer 8

1. Classical pathway e.g. IgM + IgG
2. MBL pathway (mannose binding lectin)
3. Alternative pathway (C3b causing feedback loop)

Question 9

Where do B cells mature?

Answer 9

Bone marrow

B = bone

Question 10

What is primary lymphoid tissue?

Answer 10

Blood and lymph

Question 11

What is secondary lymphoid tissue?

What happens here? What 2 things are required for this to take place?

Answer 11

lymph nodes
spleen
MALT

B cells become activated
Antigens and T helper cell signals must be present for ^^ to occur

Question 12

Where do antigens bind to on antibodies?

What part of antibody binds to cells?

What antibody can act as a powerful opsonin as phagocytic cells have receptors for this class of antibodies heavy chain?

Answer 12

Variable region sites of antibody

Heavy chain body of cells

IgG (makes it more efficient than IgM)

Question 13

Define aggulatination

Answer 13

clumping of antigens together to enhance phagocytosis

Question 14

What antibody is found in blood as a pentameric shape? It is also the largest antibody-type

Answer 14

IgM

5 point on M

Question 15

What is the 1st antibody produced?

Answer 15

IgM

Question 16

What antibody can be transferred by mother to foetus via placenta?

Answer 16

IgG

Question 17

Why is IgA important?

Answer 17

Neonatal immunity (transferred from mother to foetus in breast milk and colostrum)

Question 18

What antibody levels drop 6 months post birth and what one starts to rise?

Answer 18

IgG drops
IgA rises

GA GA
G first in womb
A through breast milk

Question 19

Where do T cells mature?

Answer 19

Thymus

T = thymus

Question 20

What are the 3 types of T cells?

Answer 20

CD4+ helper
CD8+ killer
Regulatory

Question 21

How do T cells work?

Answer 21

recognise peptide antigens presented to the TCR (T cell receptors) found on T cells

Antigens are presented by MHC molecules

Question 22

What is the role of MHC?

Answer 22

Only needed by T cells

Display peptide antigens to TCR (T cell receptors) on T cells

Question 23

What are the 2 types of MHC and on what cells do you find each type?

What CD cell does each bind to?

Answer 23

MHC I
- present on all nucleated cells

MHC II
- present on APCs (MACROPHAGES AND DENDRITIC CELLS)

MCH I -> CD8+
MCH II -> CD4+

Question 24

Types of hypersensitivity

Give an example of each type, name cells involved and explain the MOA of each type of reaction

Give time frame for each type of reaction

Answer 24

Remember as A B C D

I - Antibody e.g. Allergy

• IgE
• mast cells and eosinophils
• seconds

II - antiBody e.g. breakdown of RBC in mismatch blood transfusions

• IgG + IgM
• NK cells
• seconds - hrs

III - immune Complex e.g acute hypersensitivity pneumonitis

• IgG
• neutrophils
• hrs - days

IV - Delayed e.g. TB, sarcoidosis, chronic hypersensitivity pneumonitis

• macrophages and T cells
• days

Question 25

What is the most abundant antibody-type?

Answer 25

IgG

Question 26

What antibody-type is secreted in breastmilk, saliva and tears?

Answer 26

IgA - (link to IgA importance in neonatal immunity)

Question 27

What regulates the adaptive response?

Answer 27

Regulatory T cells

Question 28

Explain what PAMPs and PRRs are

Answer 28

Think of a weaker antigen and antibody PAMPs (pathogen assoc. molecular patterns) - found on pathogens - (think of as a lesser antigen) PRRs (pathogen recognition receptors) - found on cells on innate system - (think of as a lesser antiobody) PAMPs and PRRs bind together

Question 29

When does a monocyte become a macrophage?

Answer 29

When it leaves the bloodstream and enters the affected tissue

Question 30

Describe the difference in appearance between basophils and eosinophils

Answer 30

BOTH bi-lobed Basophil - blue granules Eosinophil - red granules

Question 31

List leukocytes from most to least common

Answer 31

``` Neutrophils Lymphocytes Eosinophils Monocytes/macrophages Basophils ``` Newton Licks Elliots Massive Balls

Question 32

For the following cells of the innate system state identifying feature macroscopically, method of killing and if they produce any cytokine: ``` Neutrophils Lymphocyte Eosinophil Monocyte/macrophage Basophil NK cells Mast cells ```

Answer 32

Neutrophil - multi-lobed - NETS, degranulation and phagocytosis Lymphocyte Eosinophil - bilobed, red granules - think ALLERGY Monocyte/macrophage - kidney bean shaped nucleus - Phagocytosis - TNF-alpha Basophil - bilobed, blue granules - effector in allergic reactions NK cells - granular - degranulation of perforin -> induce apoptosis - INF-gamma Mast cells - .. - degranulation of histamine + heparin etc.

Question 33

What cell travels across the endothelium via transendothelial migration? What do the cells bind to on the vascular endo?

Answer 33

Neutrophils Adhesion molecules (selectins and ICAM-1) (travel across via diapedesis)

Question 34

What 3 cells are associated with allergic response? What antibody is associated?

Answer 34

Eosinophils Basophils Mast cells IgE

Question 35

What are the 5 effects of acute inflam? What system is responsible for acute inflam?

Answer 35

``` Tumour - swelling Dolor - pain Calor - heat Rubor - redness Functio laesa - loss of function ``` Innate

Question 36

What antibody is present in secretions such as breast milk and colostrum (first secretion from mammary glands post birth)?

Answer 36

IgA

Question 37

What antibody is most abundant in body?

Answer 37

IgG

Question 38

For each of the following immune-deficency disorders describe their pathology: ``` X-linked agammaglobulinaemia DiGeorge Syndrome Kostmann syndrome Reticular dysgenesis (most severe form of SCID) SCID (severe combined immunodeficiency) ```

Answer 38

X-linked agammaglobulinaemia - no B cells DiGeorge Syndrome - no T cells Kostmann syndrome - neutropenia Reticular dysgenesis - failure to produce WBC SCID - no B and T cells

Question 39

What T helper cells help macrophages and what ones help B cells?

Answer 39

TH1 - macrophages | TFH - B cells

Question 40

Which WBC is most likely to deal with large parasites that cannot be phagocytosed?

Answer 40

Mast cells

Question 41

What do B cells do?

Answer 41

Produce antibodies | B cells = antiBodies

Question 42

Name the 3 soluble mediators of the innate response?

Answer 42

Complement CRP Cytokines

Question 43

What is measured in anaphylaxis - measure of mast cell degranulation?

Answer 43

Serum tryptase

Question 44

Antibody producing cells. Fully differeniated

Answer 44

Plasma cells