L01

Question 1

what is a pathogen

Answer 1

an organism that causes disease e.g.

bacteria
viruses
fungi
parasites
worms
protozoa

Question 2

what are the features of specific immunity

Answer 2

is induced by exposure to a particular infection

shows a high degree of specificity

exhibits “memory”

mediated by lymphocytes (B/T cells)

clonally distributed receptors

large repertoire: low frequency of cells specific for any antigen

response takes time to develop
memory cells produced
(work better and faster next time)

Question 3

what is clonal selection theory

Answer 3

removal of potentially self reactive immature lymphocytes (Self antigen receptor cells are destroyed to avoid auto immune reactions)

creating a pool of mature naive lymphocytes that react to foreign antigens

Question 4

which receptor is always membrane bound

Answer 4

TCR

Question 5

what is BCR called when released after B cell activation

Answer 5

antibody

Question 6

what does TCR do

Answer 6

recognizes peptide fragment
of antigen bound to MHC
expressed by APC

Question 7

what do TCR only recognize

Answer 7

peptides

Question 8

what is the variable region of an antibody

Answer 8

form 2 identical antigen binding sites from heavy and light chains

Question 9

what is the constant regions of an antibody

Answer 9

regions responsible for the structure of the antibody and interacting with other molecules (FcR, Compliment system) and cells of innate system
—-> antibody effector functions

Question 10

what type of bonds hold the light and heavy chains

Answer 10

covalent and non-covalent

Question 11

what are the types of light chains

Answer 11

λ & κ

Question 12

how many types of light chains is present in 1 antibody

Answer 12

1

Question 13

Each chain in an antibody has a variable and a constant region

Answer 13

true

Question 14

what does the antigen binding site consist of

Answer 14

VH and VL

Question 15

what are the classes of antibodies (isotypes)

Answer 15

IgM, D, A, G and E

Question 16

what determines the isotypes of antibodies

Answer 16

heavy chain (C region)

Question 17

how many domains does the L chain have

Answer 17

2

Question 18

how many domains does the H chain have

Answer 18

4 or 5

Question 19

how long is each domain

Answer 19

110 amino acids

Question 20

what does each domain comprise

Answer 20

two b sheets

Question 21

what are the antibody domains linked by

Answer 21

disulphide bridge (S-S, C)

Question 22

domains are paired –> folded units within the protein

Answer 22

True

Question 23

how many hypervariable regions (CDRs) are there in in the VH and VL

Answer 23

3 in each

Question 24

how many antigen binding sites does 1 antibody have

Answer 24

2

Question 25

how many hypervariable loops are there in each Ag binding site

Answer 25

6

Question 26

how many hypervariable loops are there in an antibody

Answer 26

12

Question 27

what are the types of antibody/antigen interactions

Answer 27

linear (continuous) epitope non-linear (structural/3D/ discontinuous) epitope

Question 28

what type of molecules can antigens be

Answer 28

All protein, polysaccharide even nucleic acids), along with non-biological molecules e.g. chemicals, metals

Question 29

what type of interactions do Ag and antibodies form

Answer 29

non-covalent interactions

Question 30

CDRs present in antibody V regions determine the specificity and the affinity of an antibody for Ag

Answer 30

true

Question 31

which parts of the antibody interact with the epitope

Answer 31

hypervariable regions (CDRs)

Question 32

what is the epitope

Answer 32

the part of the antigen that is recognized by the antibody

Question 33

TCR binds free antigen

Answer 33

false

Question 34

antigen is presented to TCR in the cleft/binding “groove” of MHC class I or class II molecules

Answer 34

true

Question 35

how many Ig-like domains does TCR have

Answer 35

4

Question 36

TCR recognizes short peptide fragments (of Ags) bound to MHC molecules on other cells

Answer 36

True

Question 37

TCRs are heterodimers. what chains do they have

Answer 37

α and β chain (sometimes γ and δ)

Question 38

what are the regions of each chain of TCR

Answer 38

a V and a C region

Question 39

which domain of TCR interact with the antigen (peptide bound to MHC molecule)

Answer 39

V domain

Question 40

how many CDRs does each chain of TCR contribute to Ag binding

Answer 40

3

Question 41

what chromosome contains the MHC gene (HLA in humans)

Answer 41

6

Question 42

how many classes of MHC molecules are there

Answer 42

2

Question 43

where is MHC class 1 expressed

Answer 43

all nucleated cells

Question 44

MHC class 1 molecule is a heterodimer: a chain (43 kD). b2- microglobulin (12 kD)

Answer 44

True

Question 45

what are the different MHC class 1 molecules in humans

Answer 45

HLA-A, HLA-B and HLA-C

Question 46

HLA-A, B and C molecules are encoded by separate a chain genes. A single (non-MHC located) gene encodes b2-microglobulin which associates with HLA-A, HLA-B and HLA-C

Answer 46

True

Question 47

a1 and a2 domains fold to form b-sheet structure known as peptide binding site (“groove, cleft”) in MHC 1 molecule

Answer 47

True

Question 48

which domains of MHC 1 are very polymorphic

Answer 48

alpha 1 and alpha 2

Question 49

a3 domain/b2-microglobulin fold into “Ig-like” domains in MHC 1

Answer 49

True

Question 50

MHC 1 has 2 transmembrane domains

Answer 50

false

Question 51

what are the features of MHC class 2 molecules

Answer 51

expression limited to APC (and cytokine-activated cells) heterodimers, a and b chains similar size (34 and 29 kD) and both transmembrane In humans three different MHC class II molecules: HLA-DP, HLA-DQ and HLA-DR a and b chains encoded by separate genes encoded within MHC both a2 and b2 domains are Ig-like

Question 52

what are the different MHC 2 molecules in humans

Answer 52

HLA-DP, HLA-DQ and HLA-DR

Question 53

how many transmembrane domains does MHC 2 have

Answer 53

2

Question 54

MHC 2 groove is more open than “groove” seen in MHC class I molecules, and binds longer peptides

Answer 54

True

Question 55

what molecule does CD8 bind

Answer 55

MHC class 1

Question 56

what domain does CD8 bind

Answer 56

MHC class I a1/a2domains stabilizing TCR/MHC interaction

Question 57

what molecule does CD4 bind

Answer 57

MHC class 2

Question 58

what domains does CD4 bind

Answer 58

binds MHC class II a2/b2 domains stabilizing TCR/MHC interaction