Final: What Happens When You Get Sick? Flashcards Preview

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Flashcards in Final: What Happens When You Get Sick? Deck (21)
1

polyclonal response

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

2

epitope

part of the antigen that binds

3

where do somatic hypermutation and affinity maturation take place?

lymph nodes

4

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

to improve binding affinity

5

what are the sites of somatic hypermutation and affinity maturation

germinal centers in the lymph nodes

6

what do hypermutation and affinity maturation do

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

7

where does class-switching recombination take place

lymph nodes

8

class switching recombination

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

9

5 types of Ig tools

IgM, IgD, IgA, IgE, IgG

10

IgE on mast cells cause

inflammation in response to allergens

11

what is a major histocompatibility complex (MHC)?

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

12

two kinds of MHC

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)

13

MHC I

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)

14

MHC II

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

15

peptide displayed in MHC must interact with...

either TCR of a helper or killer t cell

16

what is an HLA gene

human leukocyte antigen

genes that make MHC proteins

short arm of chromosome 6

17

HLA genes

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

18

the HLA genes have a huge number of _____

alleles

3 main MHC I genes have hundreds of alleles

3 main MHC II genes have about 100 alleles

19

HLA haplotype

set of HLA alleles on one chromosome

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

20

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

see

diversity is an advantage in MHC I & II receptors

21

problem with organ transplants

MHC diversity

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

HLA haplotypes of donor and recipient must be matched