Immunology - Innate Immunity

Question 1

What is the precursor to cells in the blood?

Answer 1

Haematocytoblast

Question 2

What 2 things do haematocytoblasts become?

Answer 2

Common myeloid progenitor
Common lymphoid progenitor

Question 3

What do the myeloid progenitors become?

Answer 3

Megakaryocyte, erythrocyte, mast cell, myeloblast

Question 4

What do myeloblasts become?

Answer 4

Eosinophils, basophils, neutrophils,
monocytes—> macrophages

Question 5

What do lymphoid progenitors become?

Answer 5

Natural killer cell (NKC)
Lymphocyte (T cell, B cell —> plasma cell)

Question 6

What cells are in which types of immunity?

Answer 6

Innate immunity- neutrophils and macrophages

Adaptive immunity- NKC, T and B cell, plasma cell

Question 7

What are primary lymphoid organs?

Answer 7

Bone marrow & thymus

Question 8

What happens in the bone marrow and thymus?

Answer 8

Bone marrow - all cells originate, B cells mature here

Thymus - T cell maturation + ‘thymic tolerance’

Question 9

Where are secondary lymphoid organs?

Answer 9

Lymph notes
Spleen

Question 10

What happens in the lymph nodes and spleen?

Answer 10

Lymph nodes - antigen presenting cell (APC) + T/B cell interactions

Spleen - RBC recycling, encapsulated bacterial killing

Question 11

What are tertiary lymph organs?
Are they normal?

Answer 11

Pathological
Germinal centers of rapidly proliferating lymphocytes

Question 12

Describe innate immunity
Specific?
Fast or slow?
Memory?
What cells are involved?

Answer 12

Non specific, rapid, already active (little activation needed), no memory
Killing usually via complement activation
Neutrophils and macrophages mainly

Question 13

What are some physical and chemical barriers in the body?

Answer 13

Physical- skin, mucus, cilia

Chemical- lysozyme in tears, stomach acid

Question 14

What does the complement system do?

Answer 14

Destroy foreign antigens by:
Direct lysis - membrane attack comp,ex formation (MAC)
Opsonisation - increased phagocytosis (C3b)
Inflammation - macrophage chemotaxis (C3a + C5a)

Question 15

Neutrophils
% of WBC?
Act in how long?
What do they express?
Key mediator in?
Function?

Answer 15

70% of all WBC
Act in hours - days
Express CD66 receptor (common for all granulocytes)

Key in acute inflammation

Function: Essentially mini bombs of N.E, myeloperoxidases (MPo) & other ROS
Phagocytosis

Question 16

Macrophages
Act in?
Where are they found?
Function?
What do they have?

Answer 16

Act in months - years
Can be circulating or resident (eg. Kupffer)
Clear apoptosis debris

Have toll like receptors, complement receptors & antibodies band & Fc component

Question 17

Where are monocytes and macrophages found?
What 3 features do monocytes, macrophages and dendritic cells have?

Answer 17

Monocytes- only in blood
They migrate to tissue
Macrophages - stay in tissue not blood

Phagocytic, present antigens, release cytokines -attract other immune cells

Question 18

Eosinophils
What do they contain?
When are they often seen?
What colour do they stain with what stain?

Answer 18

Contain major basic protein (MBP)
Often seen in parasitic infection
Stain pink with eosin

Question 19

Where are mast cells and basophils found?
What are their function?

Answer 19

Mast cells = fixed at tissues
Basophils = circulating in body

IgE binding = degranulation = histamine release
T1 sensitivity

Question 20

NK cells
What are they a key role in?
Function?

Answer 20

Key role in viral cell killing, self cell killing + malignant cell killing
Activation = degranulation—> perforin (perforated viral infected cells)

Question 21

Receptors on these cells are?

Answer 21

Toll like receptors + nodlike receptors

Question 22

TLRs detect different things such as:
2, 3, 4, 5, 7, 8, 9

Answer 22

2 - detects gram + & TB
3 - intracellular
4 - LPS (-) (lipopolysaccharide on gram - bacteria)
5 - flagellin
7 - single strand RNA
8- intracellular
9 - non methylated DNA

Question 23

Which TLRs are intracellular?
Where are the rest?

Answer 23

3, 7, 8, 9
Rest are on CSN (extracellular)

Question 24

What are non cell band receptors, free In blood called?

Answer 24

Lectins

Question 25

What do lectins respond to?

Answer 25

PAMPs
DAMPs
Pathogen/damage associated molecular patterns

Question 26

What are antigen presenting cells?
Which are the best type of APC?
What do they do?

Answer 26

Interface between innate and adaptive immunity

Dendritic cells
Present foreign antigens to T helper cells to either stimulate further Th proliferation or stimulate B cell production to antibodies

Question 27

When dendritic + T cells communicate, they form?

Answer 27

Immune synapses

Question 28

What 3 conditions must be met to function?

Answer 28

Receptor binding
Co stimulation (other molecules bind after 1^ receptor binding)
Cytokines release
…..otherwise no response (anergy)