Final: What Happens When You Get Sick?

Question 1

polyclonal response

Answer 1

b cell that binds an antigen is recruited by t cells and sent to the lymph nodes

Question 2

epitope

Answer 2

part of the antigen that binds

Question 3

where do somatic hypermutation and affinity maturation take place?

Answer 3

lymph nodes

Question 4

why do b cell clones that already bind the antigen go to the lymph nodes?

Answer 4

to improve binding affinity

Question 5

what are the sites of somatic hypermutation and affinity maturation

Answer 5

germinal centers in the lymph nodes

Question 6

what do hypermutation and affinity maturation do

Answer 6

mutates antibody gene where the hypervariable parts of the protein are coded

all 3 hypervariable regions of both hvy and light chains are mutated

if new antibody has a higher affinity they multiply and mutate again

if lower affinity they die

Question 7

where does class-switching recombination take place

Answer 7

lymph nodes

Question 8

class switching recombination

Answer 8

somatic hypermutation stops after antibody has high affinity

the cell then works on the constant part of hvy chain

DNA splicing takes place

puts 1/5 “Ig” tool onto the constant region

Question 9

5 types of Ig tools

Answer 9

IgM, IgD, IgA, IgE, IgG

Question 10

IgE on mast cells cause

Answer 10

inflammation in response to allergens

Question 11

what is a major histocompatibility complex (MHC)?

Answer 11

3rd kind of surface cell receptor attached to membranes of most cells in the body, not just immune cells

bind and display short polypeptides ~10 aas (chopped up proteins) on cell surface

hold pp in a groove

Question 12

two kinds of MHC

Answer 12

MHC I displays fragments of proteins from inside the cell (endogenous proteins)

MHC II displays fragments of proteins taken from outside the cell (exogenous proteins)

Question 13

MHC I

Answer 13

almost all cells in the body display MHC I

important in weeding out infected or cancerous cells

constantly checked by killer t cells (CD8)

if foreign fragment, killer t kills (kiss of death)

simplist way to rid body of infection (viral)

Question 14

MHC II

Answer 14

important in directing b cells to secrete antibodies

MHC II checked by helper t cells (CD4), which bind the antigen the antibody is holding (handshake)

this stimulates b cell to turn into plasma cells and go to the lymph nodes

leads to somatic hypermutation and affinity maturation

Question 15

peptide displayed in MHC must interact with…

Answer 15

either TCR of a helper or killer t cell

Question 16

what is an HLA gene

Answer 16

human leukocyte antigen

genes that make MHC proteins

short arm of chromosome 6

Question 17

HLA genes

Answer 17

MHC I genes are in one place and MHC II in a different place

each chromosome 6 has multiple versions of MHC receptors

these are multiple genes that code for different versions of MHC I & II

MHC I and MHC II genes are always expressed togehter

Question 18

the HLA genes have a huge number of _____

Answer 18

alleles

3 main MHC I genes have hundreds of alleles

3 main MHC II genes have about 100 alleles

Question 19

HLA haplotype

Answer 19

set of HLA alleles on one chromosome

a person has 2 HLA haplotypes and all alleles are expressed at the same time

Question 20

HLA diversity increases the number of ways the immune system can ___ proteins

Answer 20

see

diversity is an advantage in MHC I & II receptors

Question 21

problem with organ transplants

Answer 21

MHC diversity

organs from other people are never a perfect match (unless identical twin)

HLA haplotypes of donor and recipient must be matched