L4

Question 1

what are CD4 t cells aka

Answer 1

helper t cells

Question 2

what are CD8 t cells aka

Answer 2

cytotoxic t cells

Question 3

how did the thymus get discovered

Answer 3

thymectomised mice
became susceptible to infection
reduced no. lymphocytes
immunodeficient

Question 4

a reason why thymic function declines with age

Answer 4

‘involutes’ ie shrinks as we age

Question 5

what 2 chains does the TCR have

Answer 5

alpha and beta
each chain has a variable region, constant region, hinge and then TM region
joined by disulphide bonds

Question 6

which signal transducing molecules is BCR associated with

Answer 6

Ig alpha
and
Ig beta

Question 7

whcih signal transdcuing molecule is TCR associated with

Answer 7

CD3

Question 8

APC

Answer 8

antigen presenting cell
must be done for T cell recognition

Question 9

What complex allows antigen to be presented

Answer 9

MHC (1 and 2)
major histocompatibility complex

Question 10

differences between MHC 1 and 2 structure

Answer 10

MHC-I has one long alpha chain that forms the TM domain, and is non cov bound to Beta 2 microglobulin chain

MHC-II has 2 chains (alpha and beta) and therefore 2 TM domains

Question 11

where are MHC I and II expressed

Answer 11

I is on most nucleated cells
II has restricted expression - macrophages, B cells

Question 12

which chain is encoded by the A, B and C loci on chromosome 6

Answer 12

alpha chain of MHC-I

Question 13

what is MHC II encoded by

Answer 13

DP, DQ and DR regions on chrom 6
(alpha and beta chain)

Question 14

which type of antigens do MHC I typically present vs MHC II

Answer 14

I = intracellular antigens e.g. viral
II = extracellular antigens e.g. parasites, bacteria

Question 15

where is antigen degraded in cell in MHC I process

Answer 15

proteosome to form peptides

Question 16

what chaperone protein is MHC Class I bound to in the ER

Answer 16

Calnexin (is removed once B2M binds)

Question 17

what chaperone protein takes calnexins place once B2M binds

Answer 17

calreticulin
and tapasin also binds which allows the TAP transporter to bind

Question 18

what does TAP tranporter do

Answer 18

delivers the peptide fragmets to bind to the MHC I molecule

Question 19

in MHCII process, where is antigen degraded

Answer 19

an endolysosome
(endosome and lysosome fuse)

Question 20

what is bound to MHC II to block binding of stuff that isnt the antigenic peptide

Answer 20

invariant chain

Question 21

when the invariant chain is cleaved, what is left bound to MHC II

Answer 21

short peptide fragment (CLIP)
this has to be removed to allow other peptides to bind

Question 22

how is CLIP removed

Answer 22

HLA-DM
allows other peptides to bind
the MHC II can then travel to the surface

Question 23

what mhc is CD4 associated with

Answer 23

class II

Question 24

what mhc is CD8 associated with

Answer 24

class I

Question 25

advantages of MHC-associated recognition

Answer 25

• extra recognition mech, harder for pathogen to evade