Public: Innate Immunity

Question 1

Give 2 instances when the immune system can be beneficial

Answer 1

Protection from invaders

Elimination of altered self

Question 2

Give 2 instances when the immune system can produce a detrimental effect

Answer 2

Discomfort (inflammation)

Damage to self (autoimmunity)

Question 3

Describe the innate immune system

Answer 3

first line of defence
rapidly invoked
non-specific

Question 4

Name 4 Innate mechanisms

Answer 4

• Anatomic resisting barriers (skin, mucous)
• Physiologic barriers (temperature, pΗ, etc)
• Phagocytosis
• Inflammatory defensive barriers (vasodilation, increase in capillary permeability, influx of phagocytes)

Question 5

Name 3 ways the epithelia has innate immunity

Answer 5

physical barrier to infection
Killing of microbes by locally-produced antibiotics
Killing of microbes and infected cells by intraepithelial lymphocytes

Question 6

Name 4 soluble factors of the innate immune system

Answer 6

Lysozymes
Acute phase proteins
Complement
Interferons

Question 7

What do lysozymes do?

Answer 7

Split the bacterial wall of susceptible bacteria

Question 8

What do acute phase proteins do?

Answer 8

Opsonisation
Attraction of phagocytes
Increased blood flow

Question 9

What does complement do?

Answer 9

Opsonisation

Question 10

Define opsonisation

Answer 10

Antibody opsonization is the process by which a pathogen is marked for ingestion and eliminated by a phagocyte. ..

Question 11

What do interferons do?

Answer 11

Antiviral resistance

Question 12

2 types of cells involved in the innate immune system and what they do

Answer 12

Phagocytes (macrophages) - engulf particles

Natural killer cells -recognise cell surface changes occurring on virally infected and tumour cells (cytotoxicity)

Question 13

Cells of the immune system family tree

Two main groups

Answer 13

Myeloid cells

Lymphoid cells

Question 14

Cells of the immune system family tree

2 groups under myeloid cells

Answer 14

Granulocytic

Monocytic

Question 15

Cells of the immune system family tree

3 types of Granulocytic cell

Answer 15

Neutrophils
Basophils
Eosinophils

Question 16

Cells of the immune system family tree

4 types of Monocytic cells

Answer 16

Macrophages
Langerhans
Kupffer cells
Dendritic cells

Question 17

Cells of the immune system family tree

2 groups under lymphoid cells and everything under them

Answer 17

T cells - T helper and T cytotoxic

B cells - plasma cells

Question 18

Draw the myeloid lineage on whiteboard

Answer 18

and check slide 11 to see if you’re right

Question 19

Describe monocytes

Answer 19

The human blood monocytes are larger cells than lymphocytes; they usually have a horseshoe-shaped nucleus and often contain faint azurophilic granules.

Question 20

Macrophages

Answer 20

They are often referred to as scavengers or antigen-presenting cells (APCs). Stimulated macrophages exhibit increased levels of phagocytosis.
-Phagocytosis, intracellular and extra-cellular killing, tissue repair, antigen presentation for specific immune response.

Question 21

Neutrophil

Answer 21

The most important cellular components in bacterial destruction. They are relatively large and most abundant white blood cells with lobed nucleus and cytoplasmic granules (lysosomes).
PMN granules are of two kinds: Primary and Secondary

Question 22

Phagocytosis steps

Answer 22

1) Binding
2) Internalisation in vacuole
3) Fusion of vacuole with lysosome
4) Digestion of bacteria
5) Exocytosis

Question 23

Basophils

Answer 23

They are found in a very small number in the circulation and are characterised by deep violet-blue granules.

• Active in allergic reactions
• Release histamine
• Bind complement C3a, C3b & C5a

Question 24

Eosinophils

Answer 24

Eosinophils gather wherever there is a parasite infection or an allergic reaction such as allergic asthma, and then release their toxins contained in their granules. They can be triggered to degranulate by appropriate stimuli.
They play important role in the defence against parasitic infections.
Allergic reactions
-Histamine release

Question 25

NK cells

Answer 25

Natural killer cells

Kill infected cells and also phagocytosed microbes

Question 26

Mast cells (concentrated under the body surfaces)
mechanism of action

Answer 26

Release factors which increase blood flow and vascular permeability bringing components of immunity to the site of infection

Question 27

Neutrophils and macrophages (phagocytes)

Answer 27

Engulf (phagocytose) and destroy micro-organisms

Question 28

Eosinophils

Answer 28

Secrete factors which kill protozoa and worms

Question 29

Natural killer cells

Answer 29

destroy virus infected cells

Question 30

Alternate pathway of complement (a system of enzymes and control proteins)

Answer 30

Activate mast cells, attract phagocytes, make micro-organisms more easily recognised by phagocytes (opsonisation), lyse micro-organisms

Question 31

Acute phase proteins (C-reactive protein, Mannose-binding lectin)

Answer 31

Activate complement and opsonise

Question 32

Cytokines - interferon

Answer 32

toxic to viruses

Question 33

Give an example of an organism resistant to phagocytosis

and its mechanism

Answer 33

Pneumococcus

Capsular polysaccharide inhibits phagocytosis

Question 34

Give an example of an organism resistant to reactive oxygen intermediates in phagocytes
and its mechanism

Answer 34

Staphylococci

Production of catalase, which breaks down reactive oxygen intermediates

Question 35

Give an example of an organism resistant to complement activation
and its mechanism

Answer 35

Neisseria meningitides - Sialic acid expression inhibits C3 and C5 convertases
And
Streptococcus - M protein blocks C3 binding to organism and C3b binding to complement receptors

Question 36

Give an example of an organism resistant to antimicrobial peptide antibiotics
and its mechanism

Answer 36

Pseudomonas

Synthesis of modified LPS (Lipopolysaccharide) that resists the action of peptide antibiotics