Immunology

Question 0

TLR4

Answer 0

Receptor on macrophage that recognises lipopolysaccharide on gram negative bacteria. LPS must have been bound by CD14 and formed a complex with MD2 to trigger system.

Question 1

PRRs

Answer 1

Pamp recognition receptors. Recognise structures characteristic of microbes that are shared by classes of organisms. Not present in host. Eg. Lipid

Question 2

NF-kB

Answer 2

Once released from inhibition, goes to nucleus and causes transcription of cytokine genes. Produce inflammation.

Question 3

NOD1 and 2

Answer 3

Bond muramyl tri and di peptides respectively.

Question 4

RIG1

Answer 4

Detects viral RNA in cytoplasm

Question 5

Inflammasome

Answer 5

Monomers of NALP3, cascade 1 and adaptor protein ASC. activated by components of microbes etc. caused production of IL-1B.

Question 6

Mast cell

Answer 6

From myeloid, contains histamine and heparin in granules. Role in allergy, anaphylaxis and wound healing. Found in tissues.

Question 7

Platelet activating factor

Answer 7

Recruits and activated neutrophils and eosinophils.

Question 8

Eosinophils

Answer 8

Produce granule proteins, ROS and enzymes. Defense against helminths. Releases granules with proteins toxic to parasite.

Question 9

Leukotrienes

Answer 9

Trigger smooth muscle contractions (overproduction in asthma). Act on GPCR to sustain inflammatory response.

Question 10

P-selectin

Answer 10

Expressed induced on endothelial cells by thrombin and histamine. Binds to glycoproteins with sialyl-lewis x group on neutrophils. Low affinity attractions.

Question 11

ICAM

Answer 11

Cause tight adhesions. Activated to high affinity state by chemokines.

Question 12

VCAM-1

Answer 12

Mediates adhesion of lymphocytes, monocytes, eosinophils and basophils

Question 13

ICAM-1

Answer 13

Mediates adhesion of lymphocytes

Question 14

Granuloma

Answer 14

Activated macrophages surrounds by activated lymphocytes (eg. t helper cells). May contain multinucleated giant cells.

Question 15

Alternative C3 convertase

Answer 15

C3bBb produced by C3 binding to surface, recruiting factor B, more susceptible to cleavage by factor D creating enzyme.

Question 16

Properdin

Answer 16

Binds to C3bBb on microbe surface and prevents its degradation. Increases half life and accelerates C3b generation.

Question 17

Factor H

Answer 17

Binds to C3b and promotes cleavage by factor I to iC3b which cannot assembly into enzyme. If depleted, susceptible to encapsulated bacteria (only phagocytosed when opsonised with complement.

Question 18

DAF (decay accelerating factor)

Answer 18

Made by host cells to inactivate C3b

Question 19

CD59

Answer 19

Glycoproteins on host cells binds to assembling MAC and prevents recruitment of C9. No pore forms and cells protected. RBCs lacking this -> red pee in morning.

Question 20

Classical C3 convertase

Answer 20

C4bC2a. C2a is, unusually, the larger fragment.

Question 21

IgA

Answer 21

Mucosal linings and secretions. Initiates inflammatory reactions.

Question 22

IgD

Answer 22

Co-expressed with I. Monomer. Role in allergic reactions. Binds to basophils and mast cells.

Question 23

IgE

Answer 23

Binds to mast cells. Important in parasitic infections. Role in type 1 hypersensitivity.

Question 24

IgG

Answer 24

Activated complement. Placental transfer.

Question 25

IgM

Answer 25

Activated complement. Pentamer.

Question 26

FcRI

Answer 26

High affinity receptor for IgG. On macrophages. Phagocytosis.

Question 27

FcRIIa

Answer 27

Low affinity. On macrophages and neutrophils. Phagocytosis

Question 28

FcRIIb

Answer 28

Low affinity on B lymphocytes. Antibody regulation.

Question 29

FcRIIIa

Answer 29

Low affinity. On NK cells and macrophages. Cause antigen dependent cell mediated cytotoxicity.

Question 30

FcRIIIb

Answer 30

Low affinity on neutrophils. Phagocytosis.

Question 31

Affinity

Answer 31

Interaction between single antibody binding site and single monovalent epitope on an antigen. Two antigen binding sites per antibody.

Question 32

Avidity

Answer 32

Strength of interaction due to recognition of polyvalent epitope a. Can bind to multiple epitopes on the same antigen.

Question 33

Th1

Answer 33

Cell mediated immunity. Activates macrophages, NK cells and CTLs. Important for intracellular pathogen infections. Stimulated by abundant antigen, high affinity TCR interactions and IL-12

Question 34

Th2

Answer 34

Eliminate parasitic infections. Humoral mediated immunity. Cytokines. Stimulated by low peptide abundance, weak affinity for TCR and IL-4. Down regulated by IFNgamma.

Question 35

Th17

Answer 35

Involved in the defense against extra cellular bacteria and some fungi.

Question 36

Complete Freund's Adjuvant

Answer 36

Contains ground-up mycobacteria which act as PAMPs.

Question 37

Myasthenia Gravis

Answer 37

Autoantibodies to ACh receptor. Reduces neuromuscular transmission from cholinergic neurons by coming and down regulating receptor