Antibodies And Gene Rearrangement

Question 1

Adaptive immunity

Answer 1

Has memory- 2nd response stronger and more rapid than first
Affinity of B cells toward antigen inc w time and persistence of antigen
Each lymphocyte = diff antigen

Question 2

What’s a transposon

Answer 2

Segment of dna that moves from one location on a chromosome to another

Question 3

What’s ancient transposase in your genome

Answer 3

RAG1 RAG2 (recombination activation genes)

Question 4

What’s recognition sequence

Answer 4

Base pair sequence found at end of any gene segments that rearranges (RS is substrate for RAGs)

Question 5

What’s immunoglobulins

Answer 5

Proteins which repeat (Ig domains) to make up antibodies. Ig protein domain fold = beta barrel 110 amino acids.

2 anti parallel beta pleated sheets joined by disulphide bond

Question 6

Antibody structure

Answer 6

2 identical heavy/light chains = 4 protein chains of repeating Ig domain

Question 7

5 Ig classes and what makes them differ (made from maturing b cells)

Answer 7

H chain makes them differ
IgM- default serum and membrane
IgG- serum
IgD- serum and membrane
IgE- serum
IgA - serum and mucosa

Question 8

What’s affinity

Answer 8

When Sum of attractive forces at 2 surfaces exceeds repulsive forces there’s affinity.
Higher affinity, fewer molecules per unit volume to associate and dissociate slowly

Question 9

What’s avidity (more improatnt than affinity)

Answer 9

Result of multiple affinity contacts. Strength/overall binding capability of antibody to target antigen
High avidity is important (more binding sites =higher)

Question 10

Complementarity is when what?

Answer 10

An antibody can bind to anything as potential amino acid diversity at binding site is vast

Question 11

Where’s amino acid variation found

Answer 11

3 discrete regions - complemetarity determining regions

Question 12

Recomb in Ig locus

Answer 12

in heavy chain - d to j combination then v to the combinated d segment gets rearranged. Joining is imprecise to make massive repitoire

Question 13

What’s clonal selection

Answer 13

Your genome makes as many receptor combinations as possible and allows pathogen to select the useful clones

Question 14

One B cell = one antigen specificity occurs where

Answer 14

In lymph nodes. Low affinity B cells form high affinity over time where some become memory cells and others become plasma cells

Question 15

Lymph node follicle anatomy

Answer 15

Has germinal centre where T cells drive B cells to undergo affinity maturation

Question 16

Affinity maturation in B cells

Answer 16

Repertoire of naive B cells generated before birth.
B cells encounter antigen in lymph nodes
some clones have higher antigen receptor
affinity
after some rounds, b cell becomes plasma cell and secretes soluble Ig and some stays in lymph nodes as memory cells.

Question 17

Immunity to tetanus

Answer 17

TT (tetanus toxin). Every baby has IgM antibodies that binds to TT weakly not enough to neutralise. Vaccinating w Tetanus Toxoid drives affinity maturation to high affinity to block TT receptor binding

Question 18

Why do we vaccinate

Answer 18

Sanitation, vaccination and antibiotics saved many lives.
Safe simple cheap effective