Immunology

Question 1

what is the innate immune system

Answer 1

Fast, natural immunity

Non specific with physical and chemical barriers

Question 2

What is the acquired immune system

Answer 2

adaptive immune system that is specific to the disease

Question 3

First line defence

Answer 3

Skin - physical barrier
Mucous - lines all body cavities
Commensal bacteria - compete with dangerous bacteria

Question 4

what is a PAMP

Answer 4

pathogen associated molecular patterns

present on pathogen surface

Question 5

what is a PRR

Answer 5

pathogen recognition receptors

bind to PAMP and initiate phagocytosis

Question 6

Describe phagocytosis

Answer 6

Macrophage binds to pathogen
engulfs and traps pathogen in a phagosome
Lysosome binds to phagosome and digests bacteria
debris released, pathogen derived peptides displayed on MHC II of macrophage

Question 7

What is an opsonin and give examples

Answer 7

pathogens coated in soluble factors opsonin to enhance phagocytosis
IgG, IgM, CRP C3b

Question 8

What do mast cells do

Answer 8

Bing to PAMP on pathogen and degranulate to release pro inflammatory substances:
Cytokines (TNFa), histamines, prostaglandins and nitric oxide

Question 9

Where are neutrophils normally found

Answer 9

bloodstream

Question 10

state the stages of neutrophil migration

Answer 10

stasis and marginalisation
chemotaxis
reactivation

Question 11

3 ways neutrophils can kill a pathogen

Answer 11

phagocytosis
degranulation
NETs

Question 12

a high neutrophil count is a hallmark _____

Answer 12

acute inflammation

Question 13

what acute phase proteins are secreted in response to acute inflammation

Answer 13

CRP
C3
MBL

Question 14

3 pathways of the complement system

Answer 14

Mannose binding lectin
Classical
Alternative

Question 15

C3 is cleaved into C3a and C3b. what do they do

Answer 15

C3a - pro inflammatory mediator

C3b - binds to cell surface with others to cleave C5

Question 16

what does C5b do?

Answer 16

binds to cell and combines to create MAC

opsonin to promote phagocytosis

Question 17

what does MAC do?

Answer 17

punctures cell membrane of pathogen to cause it to urst

Question 18

what is the function of interferons in virally infected cells

Answer 18

causes surrounding cells to destroy their DNA and reduce protein synthesis

Question 19

How do NK cells work?

Answer 19

MHC I protein with self peptide on healthy cell binds to inhibit NK cell
infected cells do not have this self peptide so are destroyed

Question 20

antibodies are made up of

Answer 20

2 light and 2 heavy polypeptide chains

Question 21

what do b cells differentiate to when activated

Answer 21

plasma cells

Question 22

what is clonal proliferation

Answer 22

rapid and identical division of B cells

Question 23

when a B cell enters a lymph node, where does it go?

Answer 23

b cell follicle

Question 24

when an antigen goes to a lymph node a B cell will be activated. one signal is the binding to the antigen. where is the second from?

Answer 24

multiple non self antigens binding multiple sites
PAMP activation on pathogen or debris surface
helper T cell

Question 25

what antibody do plasma cells initially secrete

Answer 25

low affinity IgM

Question 26

IgM affinity secreted from B cells is increased by what?

Answer 26

helper T cells causing B cell to introduce point mutations

Question 27

true/false - following helper T cell increasing IgM affinity the B cell switches antibiody class to IgG

Answer 27

true

Question 28

what is the function of the heavy chain on antibodies

Answer 28

activates complement

Question 29

IgM functions

Answer 29

b cell activation - monomer | b cell secretion - pendamer

Question 30

how does IgM activate complement

Answer 30

binding site for C1 which forms an enzyme to cleave C3

Question 31

true/false - IgM cannot enter body tissues

Answer 31

true - it is too large so stays in secretions and plasma

Question 32

functions of IgE

Answer 32

allergic responses

Question 33

where are IgA monomers found

Answer 33

serum

Question 34

where are IgA dimers found

Answer 34

sweat saliva breast milk tears

Question 35

Functions of IgG

Answer 35

``` foetal immunity complement activation opsonisaton NK activation virus neutralisation ```

Question 36

true/false - t cells can recognise all antigens

Answer 36

false - only peptide antigens

Question 37

when can a t cell recognise a peptide antigen

Answer 37

when presented on MHC

Question 38

class I MHC is expressed on ____ and presents antigens to ___

Answer 38

all nucleated cells | CD8+T cells

Question 39

class II MHC is expressed on ___ and presents antigens to ____

Answer 39

antigen presenting cells | CD4+T cells

Question 40

how does an APC activate CD4/CD8 T cells

Answer 40

presents peptide from phagocytosis to T cells and confirms signal with co-stimulatory molecule

Question 41

CD4+T cells differentiate into TH0 cells followed by

Answer 41

TH1 TH2 TFH

Question 42

what do TH1 cells do

Answer 42

secrete pro inflammatory cytokines to kill internal pathogens via ROS - assist macrophages

Question 43

what do TFH cells do

Answer 43

bind to B cell via MHC II to assist the cell differentiate into a plasma cell allow B cells to secrete better affinity antibodies

Question 44

what interleukin causes TFH cell proliferation

Answer 44

IL-2

Question 45

what do CD8+T cells proliferate into

Answer 45

cytotoxic T lymphocytes

Question 46

function of CTLs

Answer 46

kill virally infected cells by apoptosis

Question 47

what interleukin proliferates CD8+T cells to CTL

Answer 47

IL-2