Basic Immunology

Question 1

What cells make up the innate immune system?

Answer 1

neutrophils, monocytes, macrophages, mast cells and natural killer cells

Question 2

How does the innate immune system detect infection?

Answer 2

pathogen associated molecular patterns (PAMPs) bind toll like receptors

Question 3

How does the innate immune system detect cell damage?

Answer 3

damage associated molecular patterns (DAMPs) bind to DAMP receptors

Question 4

Which chemokines and cytokines are released when TLRs and DAMP receptors are activated?

Answer 4

IL-1beta, TNFalpha, IL-6, CXCL8, IL-12

Question 5

What is the outcome of the complement system?

Answer 5

the membrane attack complex

Question 6

How is the complement system activated?

Answer 6

either via the classical pathway, the lectin pathway or the alternative pathway

Question 7

What is the central junction for all the complement pathways?

Answer 7

C3 convertase

Question 8

How is the classical complement pathway activated?

Answer 8

antigen-antibody binding

Question 9

How is the lectin complement pathway activated?

Answer 9

mannan-binding lectin binds mannose on pathogen surfaces

Question 10

What happens to patients that have a deficiency of C1q, C1r, C1s and C4?

Answer 10

immune complex deposition in tissues leading to glomerulonephritis

Question 11

What happens to patients that have a deficiency of late complement pathway?

Answer 11

can’t make a membrane attack complex so are immunodeficient and get infections particularly to neisseria meningitidis

Question 12

What happens to patients that are deficient in C1 esterase inhibitor?

Answer 12

hereditary angioneurotic oedema

Question 13

What is complement induced HUS?

Answer 13

either genetic or autoimmune disease leading to deficiency of complement regulatory proteins which causes renal failure and organ failure

Question 14

How do you differentiate complement induced HUS from TTP and infection induced HUS?

Answer 14

ADAMTS13 normal, shiga toxin negative

Question 15

How do you treat complement induced HUS?

Answer 15

eculizumab - a monoclonal antibody which blocks cleavage of C5 - however this means that can’t make MAC so need to be vaccinated against neisseria

Question 16

Where do you find MHC I?

Answer 16

on all nucleated cells

Question 17

Where do you find MHC II?

Answer 17

on antigen presenting cells, dendritic cells, B cells and macrophages

Question 18

What is the role of the thymus?

Answer 18

in late fetal life all T cells go to the thymus where thymic epithelial cells express most self peptides - if there is binding then those T cells undergo apoptosis

Question 19

What is AIRE?

Answer 19

a transcription factor in thymic epithelial cells for expression of self peptides

Question 20

What is required for T cell clonal proliferation?

Answer 20

need antigen to presented by MHC, need second activating signal (CD40, CD80, CD86)

Question 21

What is the role of CD4 T cells?

Answer 21

recruit and activate innate leukocytes

Question 22

What is the role of CD8 T cells?

Answer 22

kill targeted cells/microbes by granzyme and perforins

Question 23

What are the 4 types of CD4 T cells?

Answer 23

TH1, TH2, TH17 and T reg

Question 24

What is the role of TH1?

Answer 24

activate macrophages, induces B cells to produce opsonising antibodies

Question 25

What is the role of TH2?

Answer 25

activates B cells to make neutralising antibodies

Question 26

What is the role of TH17?

Answer 26

protects against intracellular pathogens e.g. candida

Question 27

What is the role of Treg?

Answer 27

secretes cytokines (IL-10 and TGF beta) with immunosuppressive properties

Question 28

What is the role of IgM?

Answer 28

complement activation

Question 29

What is the role of IgG?

Answer 29

opsonisation and phagocytosis, complement activation

Question 30

What is the role of IgE?

Answer 30

immunity against helminths, mast cell degranulation

Question 31

What is the role of IgA?

Answer 31

mucosal immunity