Organisation Of The Immune System

Question 1

What are some other names for the innate and adaptive immune systems?

Answer 1

Innate: Natural or Non specific

Adaptive: acquired or specific

Question 2

Name the six non-cellular innate defences

Answer 2

Skin

Saliva (Antibacterial enzymes)

Tears (Antibacterial enzymes)

Mucus lining

Stomach acid

Good gut bacteria

Question 3

Name the 3 granular cell types (granulocytes) of the innate immune system and their function?

Answer 3

Neutrophil (90% of Granulocytes) - phagocytosis

Eosinophils (2-5%) - destroys parasites

Basophils (0-2%) - inflammation

Question 4

what is an antigen?

Answer 4

A foreign substance that causes a reaction from the immune system. E.g influenza

Question 5

What is a Pathogen?

Answer 5

A microscopic organism that causes sickness

E.G bacteria and viruses

Question 6

What is Bacteria and it structure?

what is bacteria with an outer membrane called?

Answer 6

Single cell, no nucleus

Can cause infections, but many species are non-infectious

come in variety of shapes (e.g rod like, spheres or spirals) and sizes.

gram negative bacteria has outer membrane

Question 7

What are virus? and how do they function?

Answer 7

Cannot express its genes without taking over a host cell

uses host to make copies of itself

Can mutate during cell division, making it harder to detect them

Question 8

What are the functions of the immune system

Answer 8

Protect
recognise
attack
destroy

Question 9

What characterises neutrophils? and what is the difference between mature and immature neurtrophils?

Answer 9

Many shaped nuclei
60% of leukocytes
life-span 2-3 days
3 day reserve in the bone marrow

mature neutrophil have more lobes. Immature have a ‘band shaped nucleus’

Question 10

Name the 4 processes of neutrophil function?

Answer 10

1) Attracted to site of infection by chemotaxins released by infected cell
2) Ingest infected tissue via phagocytosis, helped by opsonins
3) Destroy by release of free radicals and cytoxic enzymes
4) Exhibit refractory period post-stimulation

Question 11

What is the difference between monocytes and macrophages?

Answer 11

Monocytes are found in blood

macrophage in the tissues

Question 12

What do Monocytes and Macrophages do?

Answer 12

Phagocytosis
release cytokines
present antigens

Question 13

What are ‘classical’ monocytes and their main function?

Answer 13

CD14++/CD16- 
anti microbial (killing cells)

Question 14

What are ‘non-classical’ monocytes and their main function?

Answer 14

CD14+/CD16++

highly pro-inflammatory

Question 15

What Cells do dendritic cells derive from? and what is their main function?

Answer 15

Derived from monocytes

their main role is to present antigens to initiate the acquired immune response

Question 16

What two things does ‘Complement’ do?

Answer 16

1) Help to amplify phagocytic response
2) Also do things directly, by forming a shape ring, binding to cell surface; piercing the cell surface causing a lesion. The cell insides leak out causing cell death.

Question 17

What are natural Killer cells? and how do they kill infected cells?

Answer 17

Large Granular Lymphocyte
Extracellular killing cell (bind to the outside of cell)

kill cells via perforin (release pins pierce the outside of target cell)
activates apoptosis (cell suicide)

Question 18

Why are NK cells labelled CD3-? and what is the difference between CD56 bright and CD56 dim?

Answer 18

CD3- is used to distinguish them from Tcells that contain CD3+.

CD56 dim NK cells are better at cytotoxic activity because they release more perforin. CD56 bright are better at proliferation

Question 19

How is the correct acquired immunity response triggered?

Answer 19

Antigen presentation called the major histocompatibility complex

Question 20

Name the overall Tcell CD badge?

Answer 20

CD3+

Question 21

Name the Helper Tcell CD badge?

Answer 21

CD4+

Question 22

Name the cytotoxic Tcell CD badge?

Answer 22

CD8+

Question 23

What do Thelper cells do?

Answer 23

Bind to MHC class II, then control and modulate the immune response. Activate cytotoxic tcells. They also form memory of antigens.

Question 24

How are cytotoxic Tcells activated? and what do they do?

Answer 24

Activated by Thelper cells or bind to MHC class I.

Function= destroy infected cells via perforin

they also form memory

Question 25

What cytokines do th1 cells release? and what do these do?

Answer 25

They release IFN-gamma, IL-2, IL-12

Their function is defence against intracellular pathogens

Question 26

What cytokines do th2 cells release? and what do these do?

Answer 26

IL-4, IL-5 and IL-13

Their function is defence against extracellular pathogens

Question 27

Tcell activation requires 2 signals. The antigen presenting cell generates the first signal via MCH. But what must be present for the second signal?

Answer 27

The APC must express CD80-86 and the Tcell must bind with CD28 for the second signal

Question 28

Why do you become more susceptible to viral infection with age?

Answer 28

Loss of CD28 on T helper cells, not allowing T cell activation

Question 29

What are the CD badge for Treg cells? and what is their function

Answer 29

CD25

Mediate immune homeostasis. Tregs suppress activation, proliferation and cytokine production of CD4+ Tcells and CD8+ Tcells

Question 30

What is the CD badge for BCells?

Answer 30

CD19 or 20

Question 31

What is the main repsonsibility of Bcells?

Answer 31

Production of antigen-specific immunogloblins or antibodies