Block 1

Question 1

pathogen sizes small-large

Answer 1

viruses, bacteria, fungi, protozoa, worms

Question 2

phagocytes

Answer 2

2-8% of WBC: monocytes, macrophages, dendritic cells
Eats stuff

Question 3

granulocytes

Answer 3

neutrophils=40-60%
eosinophils=1-4%
basophils and mast cells=0.5-1%
release toxic compounds

Question 4

natural killer cells

Answer 4

2-3% of WBC
type of lymphocyte
kill virally infected cells and tumour cells

Question 5

CD8+ cytotoxic T cells

Answer 5

20% of WBC
kill virally infected cells, tumour cells and allografts

Question 6

CD4+ helper T cells

Answer 6

45% of WBC
Th1, Th2, TH9, TH17, regulatory T cells (Treg)
Help other cells by releasing cytokines
Regulate immune responses

Question 7

Gamma delta T cells

Answer 7

5% WBC
immunoregulatory and cytotoxic

Question 8

B cells

Answer 8

23% WBC
make antibodies

Question 9

complement pathways

Answer 9

classical, alternative, lectin

Question 10

what do the complement pathways result in

Answer 10

-phagocytosis by opsonising antigens
-inflammation by attracting macrophages and neutrophils
-membrane attack by rupturing cell wall of bacteria to lyse cells

Question 11

what are cytokines

Answer 11

hormone-like secreted proteins that act through cell surface receptors

Question 12

what do cytokines include

Answer 12

chemokines, interferons, interleukins, lymphokines and tumour necrosis factors

Question 13

what are antibodies (Ig)

Answer 13

large Y-shaped proteins produced by plasma B cells that specifically recognise pathogen epitopes

Question 14

main functions of antibodies

Answer 14

neutralisation, aggulation, complement

Question 15

what do PAMPS bind to in the innate immune system

Answer 15

patter recognition receptors (PRRs)

Question 16

classical complement pathway

Answer 16

antigen: antibody complexes activated =>recruitment of inflammatory and immunocompetent cells

Question 17

lectin complement pathway

Answer 17

lectin binding to pathogen surfaces=> opsonisation of pathogens

Question 18

alternative complement pathway

Answer 18

pathogen surfaces=> killing of pathogens

Question 19

B cell activation includes MHC-I or MHC-II

Answer 19

MHC-II

Question 20

what T cell involved in B cell activation

Answer 20

CD4+ via CD40

Question 21

where are T cells selected

Answer 21

Thymus

Question 22

where do T cells mature and migrate into

Answer 22

The periphery

Question 23

where do T cells circulate

Answer 23

through lymph nodes

Question 24

IgG

Answer 24

main antibody in the blood, binds to bacteria and toxins. Only isotope that can pass through placenta

Question 25

IgM

Answer 25

mainly distributed to the blood, produced first upon pathogen invasion by B cells, key role in initial immune system defence

Question 26

IgA

Answer 26

In secretions of bowel fluid, nasal discharge and saliva to prevent bacterial invasion from a mucous membrane. Present in breast milk and products of the gastrointestinal tract of newborns

Question 27

IgD

Answer 27

present on the surface of B cells and plays a part in the induction of antibody production at the prevention of respiratory tract infections

Question 28

IgE

Answer 28

Originally related to parasites. By binding to mast cells it is involved in allegories

Question 29

what enzyme is involved in complement pathway

Answer 29

proteases- catalysis proteolysis which breaks down proteins into smaller polypeptides

Question 30

what does classical activation require

Answer 30

IgG and IgM

Question 31

what is classical activation initiated by

Answer 31

C1 components

Question 32

what does c1 cleave

Answer 32

C4 to form C4a and C4b. C4b then binds to pathogen and C2

Question 33

what does the formation of c4b2a cleave

Answer 33

C3 which cleaves into C3a and C3b

Question 34

what does C4b2a3b cleave

Answer 34

C5 which binds to surface of pathogen and then binds to C6, C7, C8 and monomers of C9 to form c5b6789n the membrane attack complex (MAC)

Question 35

what is the alternative pathway initiated

Answer 35

C3 which is enzymatic cleaved by microbe to give C3b.

Question 36

what does C3b bind to

Answer 36

Complement factor B form C3Bb complex. Exposes a site on Factor B that is a substrate for Complement factor D Factor D cleaves Factor B to Ba and Bb C3b and Factor Bb form C5 convertase (C3bBb) - Complement factor Properdin binds to C3bBb and stabilizes it on a pathogen’s surface

Question 37

what does C3bBb forms make a complex with

Answer 37

C3b to form a C5 convertase activity Pathway then continues in same way as classical pathway

Question 38

what is the lectin pathway initiated by

Answer 38

mannan-binding protein, MASP-2 cleaves C4 and C4b-bound C2, generating C4b2a - lectin pathway C3 convertase, Continues as classical pathway

Question 39

what do lysozymes break down

Answer 39

carbohydrate chains, and damages structural integrity of the bacterial outer membrane.

Question 40

what do defensins do

Answer 40

disrupt membrane of the pathogen

Question 41

where are cathelicidins stored

Answer 41

neutrophil granules as inactive precursors