Antibody

Question 1

What are the 2 fragments of an antibody

Answer 1

Fab = Fragment antigen binding
Fc = Fragment crystalizable

Question 2

Which chromosomes contains their genes coding for the light chains and what are their names?

Answer 2

Kappa = Chromosome 2
Lambda = Chromosome 22

Question 3

Which chromosome contains the heavy chain gene

Answer 3

Chromosome 14

Question 4

How is variation in antibody derived from?

what is the full form

Answer 4

VDJ recombination

V = Variable region
D = Diversity region
J = Junction region
C = Constant region

Question 5

Light chain contains genes from what regions

Answer 5

Variable region
Junction region
Constant region

Question 6

Heavy chain contains genes from what region?

Answer 6

Variable region
Diversity region
Junction region
Constant region

Question 7

What else gives rise to variation in BCR formation other than VDJ recombination

Answer 7

Random nucleotide addition during VDJ recombination also gives rise to variation in Ab pool

Question 8

B-cell embryology

Answer 8

Lymphoid progenitor => VDJ recombination of heavy chain gene => preBCR presentation, positive selection => VDJ recombination of light chain gene => BCR presentation

Question 9

Affinity vs avidity

Answer 9

Affinity is the strength of binding of one Fab to the antigen
Avidity is the combined strength of binding to antigen via all the binding sites of the antibody

Question 10

Different types of immunoglobulins and what are their function?

Answer 10

Ig M = compliment activation
Ig A = found in mucosal sites
Ig G = cause lysis of pathogen
Ig E = cause mast cell degranulation and provides antiparasitic immunity

Question 11

What is the name of the initial immunoglobulin produced and how does it change from one type of immunoglobulin to another type of immunoglobulin

Answer 11

IgM is the initial type of immunoglobulin produced

The type of immunoglobulin produced can be changed via isotype switching

Question 12

What type of cell presents antigen to BCR and how does it present antigen

Answer 12

Follicular dendritic cell presents antigen to BCR in the form of iccosomes

Question 13

Where does affinity maturation take place and how does it occur

Answer 13

Affinity maturation takes place inside the inside the germinal centre of B cell follicule
It occurs through Somatic hypermutation via AID, Activation Induced Cytidine Deaminase
It converts cytidine to uracil and repair induces mutation in rare occasions which vary specificity to ensure that only highly specific B cells bind to iccosomes and then go on the bind to T helper cell to recieve survival and differentiation signal