Block A

Question 1

True/False: The innate immune system is specific

Answer 1

False, its non-specific. Aquired is specific

Question 2

True/False: Innate immune system is inherited

Answer 2

True, does not require prior exposure like the adaptive does

Question 3

What cellular responses first occur in the innate immune system

Answer 3

Phagocytosis, Inflammation responses and antimicrobial protein production

Question 4

In the innate immune system, what’s the importance of receptors (3 marks)

Answer 4

-recognising invaders
-recruiting different cells
-producing proteins that facilitate destruction of proteins

Question 5

Phagocytes engulf and destroy particles by ________

Answer 5

endocytosis

Question 6

Name 5 professional phagocytes

Answer 6

-neutrophils
-monocytes
-macrophages
-mast cells
-dentritic cells

Question 7

How do phagocytes move

Answer 7

Chemotaxis

Question 8

What are sentinels

Answer 8

Resident phagocytes that most tissues contain

Question 9

Name the role of neutrophils

Answer 9

First responders in inflammation

Question 10

Name the role of macrophages

Answer 10

Highly phagocytic, engulf many pathogens

Question 11

Name the role of mast cells

Answer 11

Produces histamine which causes inflammation

Question 12

Name the role of dentritic cells

Answer 12

Act as a bridge between innate and adaptive immune systems

Question 13

Describe the process of phagocytosis (6 marks)

Answer 13

-recognition and ingestion of the pathogen
-phagosome formation
-phagosome and lysosome fusion
-digestion of phagosome
-waste
-antigen presentation

Question 14

Describe how inflammation is stimulated

Answer 14

-Phagocytes are activated by Pattern Recognition Receptors (PRRs)
-PRRs recognise Pathogen Associated Molecular Patterns (PAMPs)
-Once PRRs recognise PAMPs, cytokines and chemokines are released by cells, these cause inflammation and a fever
-Histimine causes vasodilation
-Vasodilation attracks neutrophils to clear pathogens and summon lymphocytes (important in adaptive immunity)

Question 15

Explain the 2 antimicrobial proteins that are important in the innate immune system

Answer 15

-interferon-inhibits viral replication inside host cells
-complement-kills microbes without phagocytosis, causes microbes to burst

Question 16

What are PAMPs

Answer 16

They are a set of microbial molecules that share a number of patterns that alert immune cells to destroy intruding pathogens

Question 17

What are DAMPs

Answer 17

A set of patterns associated with damaged cells

Question 18

Describe how cytokines can instruct a target cell to die

Answer 18

Can instruct a target cell to increase or decrease enzyme activity so it dies.

Question 19

Name the role of chemokines

Answer 19

They attract immune cells to the site of infection

Question 20

How do B and T cells form

Answer 20

They both develop in the bone marrow from haematopoietic stem cells. Immature B cells are found in the bone marrow, mature B cells move to the lymphoid organs. T cells move to the thymus.

Question 21

Explain how B cells get a B cell receptor (BCR)

Answer 21

Re-arrangements of the immunoglobulin occur within the cell so that an unique BCR receptor is formed on the immature B cells

Question 22

What is an Immunoglobulin

Answer 22

Aka an antibody, composed of 4 linked polypeptides, 2 long heavy chains, 2 short light chains

Question 23

What is the role of IgM and IgG (2 marks)

Answer 23

-The most abundant Ig in mammals
-Provides specific immunity against viruses and bacteria

Question 24

What is the role of IgE (1 mark)

Answer 24

-Defend against parasites and allergic responses

Question 25

What is the role of IgA (2 marks)

Answer 25

-Secreted in the lining of GI tract and respiratory tract to protect locally -Major antibody found in breastmilk

Question 26

Which region on an antibody binds to an antigen

Answer 26

Variable region

Question 27

Whats an epitope

Answer 27

The binding site on a antigen

Question 28

Describe how a B cell activates.

Answer 28

-BCR is activated by antigens and by cytokines from a Helper T Cell -Once activated, B cells proliferate into plasma cells that produce antibodies and some memory cells -Memory cells are dormant waiting for a future attack of same pathogen

Question 29

What is opsonisation

Answer 29

When a pathogen is marked for phagocytosis

Question 30

How does the body prevent autoimmunity

Answer 30

-an APC presents an immature T cell with MHC -T-cells which react moderately are positively selected, recieving signals for survival -those that recognise the MHC too strongly or too little are sent signals for apoptosis, and negatively selected

Question 31

Whats a Major Histocompatibility Complex (MHC)

Answer 31

A group of genes that code for proteins that recognise and present peptides from pathogens on the surface of a cell

Question 32

Describe how an antigen is broken down (3 marks)

Answer 32

-antigen is taken up into intracellular vesicle -endosomal proteases are activated to degrade antigen into peptide fragments -vesicle containing peptides fuses with vesicle containing MHC class II molecules

Question 33

State the role of MHC I molecules

Answer 33

They are found in the membrane of almost all cells

Question 35

Which MHC class does CD4+ go with

Answer 35

MHC II

Question 36

Which MHC class does CD8+ go with

Answer 36

MHC I

Question 37

What purpose does CD4+ T cells serve

Answer 37

CD4+ activates other immune cells and is a T helper cell

Question 38

What purpose does CD8+ T cells serve

Answer 38

CD8+ kills infected cells and other pathogens and are killer cells

Question 39

Which cytokines to memory T cells require, to promote survival

Answer 39

IL-7 and IL-5

Question 40

Name and state the role of small proteins secreted by virus-containing cells

Answer 40

Interferons, these are released by infected cells and activate other immune cells to fight the virus.

Question 41

Which antibody activates complement

Answer 41

IgM

Question 42

The antibody molecule is held together by ___ bonds

Answer 42

disulfide

Question 43

In clonal selection of B cells, which substance is responsible for determining which cells become cloned

Answer 43

Antigen

Question 44

Which ONE antibody is the most important in protecting against gut infections?

Answer 44

IgA

Question 45

Which ONE antibody is most abundant in body fluids?

Answer 45

IgG

Question 46

Which ONE antibody is predominantly present in breast milk and colostrum?

Answer 46

IgA

Question 47

Which one of the following exists as dimer in secretions via J-chain?

Answer 47

IgA

Question 48

How do B cells swicth the class of antibodies they secrete (2 marks)

Answer 48

-Helper T cells secrete cytokines -that cause gene rearrangement in the B cell.