Antibodies, Antibody diversity and T cell Development

Question 1

B cells are _____ part of immune response whereas T cells are ____ immune response

Answer 1

humoral, cell mediated

Question 2

“memory cells” are unique to what part of the immune system, innate or adaptive ?

Answer 2

adaptive immune response

Question 3

what Ab cell can recognize naked Ag

Answer 3

B cells

Question 4

when would clonal expansion occur ?

Answer 4

Starts after one Ag-specific cell is activated via binding of an Ag

Question 5

what is hematopoeisis

Answer 5

formation of blood cells in bone marrow

Question 6

what is the difference in where B and T cells fully mature

Answer 6

B cells mature in bone marrow

T cells mature in thymus

Question 7

what is the difference b/w positive and negative selection of lymphocytes

Answer 7

Positive selection - means they bind self-Ag w/low avidity so they are kepl
Negative selection - bind self-Ag w/high avidity = deleted

Question 8

in what organ do B cells develop their specificity for antigens

Answer 8

spleen

Question 9

what are the 2 primary functions of B cell antibodies

Answer 9

1 - Recognize and bind naked Ag

2 - Trigger elimination of foreign Ag

Question 10

What are the two fragment regions of an Ab ?

Answer 10

Fab - antigen binding fragment

Fc - crystalline fragment

Question 11

explain the chain structure of an Ab

Answer 11

2 heavy chains spanning Fab and Fc

2 light chains spanning Fab only

Question 12

which immunoglobin (Ab) is pentameric in structure

Answer 12

IgM

Question 13

what Ab isotype is found most commonly in mucosal areas like saliva, tears etc

Answer 13

IgA

Question 14

What Ab isotypes are B cell receptors

Answer 14

IgD

IgM

Question 15

what Ab isotype is prevalent in allergies and parasitic infections

Answer 15

IgE

Question 16

which Ab isotype is most prevalent in the blood serum and can cross the placental border

Answer 16

IgG

Question 17

In Ab isotype IgG the Fab and Fc region are linked by the _____ ?

Answer 17

hinge

Question 18

the 2 light chains of IgG exist in what two forms ?

Answer 18

kappa and lambda

Question 19

what are the 4 subclasses of IgG

Answer 19

gamma 1, gamma 2, gamma 3, gamma 4

Question 20

what is antibody diversity

Answer 20

the ability to produce billions of different Ab even though there are only 20-25 k genes that code for them

Question 21

how is the human body able to accomplish Ab diversity and create so many different Ab with such few genes ?

Answer 21

B/c the heavy chain variable region is made up of 3 different segments/regions and can make countless combinations b/w these

Question 22

what are the 3 segments/regions of the heavy chain variable region in B cells

Answer 22

V (variable) - 100 genes
D (diversity) - 30 genes
J (joining) - 6 genes

Question 23

what does V(D)J recombination mean

Answer 23

accounts for combinatorial diversity through the joining of various gene segments in B cells

Question 24

what does somatic hypermutation mean and when does it occur

Answer 24

ability to make single base changes in the V(D)J genes to allow for a higher affinity of the Ab of B cells
-occurs after the Ab FIRST discovers its Ag

Question 25

B cell receptors on a naive B cell can only be what isotype

Answer 25

IgD or IgM

Question 26

explain class switching (isotype switching) w/regards to B cells

Answer 26

allows for production of multiple Ab isotypes (via plasma cells) w/same Ag specificity
Good for B cells cuz navie B cells can only be IgD or IgM isotypes

Question 27

what is the loop and cut process

Answer 27

this occurs after a plasma cell decides what Ab isotype it wants to secrete, then it loops and cuts out ALL other genes that potentially could make diff. isotype

Question 28

what are the 3 types of T cells

Answer 28

CD8 cytotoxic t cells
CD4 helper t cells
gamma mu t cell

Question 29

what are the 3 selection strategies for t cell lymphocytes after they have been transferred to the thymus

Answer 29

Positive selection - can bind (see) MHC and bind self-Ag w/low avidity
Lack of Positive selection - binds self-Ag w/low avidity but CANT bind (see) MHC
Negative Selection - can bind MHC but binds self-Ag with HIGH avidity = deleted

Question 30

in general what is the name of the effector lymphoocyte cell that secretes/produces the Ab isotypes

Answer 30

plasma cell

Question 31

an effector cell is known as an ______ cell

Answer 31

active