chapter 6 - antigen receptor genes

Question 1

There is no limit to the number of antigens that can be recognized, so how do receptors recognize them all?
we don’t have a receptor for every combination so..

Answer 1

genes get rearraged at the DNA lelvle and we can recognize these rearrangments

the immune systems has multiple genes and “re-use” the same genes

Question 2

How does the inherotance of most genes owrk

Answer 2

maternal and paternal DNA that combines through fertilization and produces patrnal form of protein and maternla form of protein

Question 3

what’s special about the gene inheritance of B cells?

Answer 3

they are clonal so one B cell produces only 1 antibody

Question 4

explain the paradigm shift found from the experiment of Hozumi and Tonegawa in 1976

Answer 4

they took embryonic liver cells and antibody-producing tumor cells and cut the DNA with restriction endonuclease

then elctrophores was done to separte by size so that the larger pieces were near the top and the lighter peices were near the bottom

these where blotted onto nitrocellulose paper detected by radiogel

they found that the DNA from antibodies had lighter segemnts meaning that DNA came toegther and lost the longer peices since only small ones where plated

Question 5

what are antibodies made of?

Answer 5

proteins made by B cells that bind an antigen

4 polypetides connected via disulfide bonds

Question 6

explain the structure of antibodies

Answer 6

4 polypetides connected via disulfide bonds

there is the light chian and the heavy chain

Question 7

where is the vraible region and tge constant region

where is the N terminus and the C terminus

Answer 7

top (two arms) - varaible region and N terminus

the bottom (one branch) - constant region and the C terminus

Question 8

where does effector activity take place?

Answer 8

the constant region

Question 9

what latin letters can the the light chain be and the heavy chain be

Answer 9

light - kappa and gamma

heavy - mew, kappa, aplpha, beta, and weird e

Question 10

where do antigens bind to the antibody?

Answer 10

the varaible region

Question 11

when an antibody is exposed to papain digestion what occurs/

Answer 11

the variable region disconnect from the constant region

Question 12

what happens when the antibody is exposed to mercaptoethanol reduction?

Answer 12

all the strand disconnect so we have two ehavy chains and two light chains

Question 13

what happnes when the antibody is exposed to pepsin digestion?

Answer 13

the lose the effector region and keep the antigen binding region

Question 14

what is the Fc part and Fab parts of the antibody?

Answer 14

Fc- consatnt region

Fab- varaible regions/ the arms

Question 15

how is the secrrted and membrane Ig the same or different then the normal antibody?

Answer 15

the secreted and membrane Ig have the same N terminus however they have different C terminuses

Question 16

where do antibodies interect with ag?

Answer 16

at the complementarity determining regions (CDR)

these CDR regions are the loops in the Fab regions

the rest ifs the framework regions

Question 17

what binds the antigen and what allows signaling into the cell?

Answer 17

binds - Fab (CDR)

Signaling into cell - Ig alpha and Ig beta

Question 18

what kind of bonds exist between the antibody and antigen?

Answer 18

non-covalent bonds

Question 19

Anti-toxin/ anti-serum/ immunity, discuss it

Answer 19

for certain disease such as tetanus and diptheria we do not develop immunity after having naturally acquired it

so we can inject a small amount of the toxin into animals such as horses, these animals then produce antigens and the serum can be taken from the animlas and injected into huamns

Question 20

what is mithridatism?

Answer 20

protection agasnit poison can be observed in reponse to small doses of poisons being ingested over time

Question 21

talk about how the isolation and discovery of antibodies was done

Answer 21

so the serum is isolated from rabbits that have been injected with Ovalbumin

electrophoresis is used to separate the proteins by size and charge

when the antibody is preincubated with the antigen there is less globulins gamma present

overall we have albumin (positive side), alpha globulun, beta globulin, and gamma globulin(negative side)

the antibodies (Ab) = immunoglobulin (Ig)

Question 22

how do agglutination reactions work?

Answer 22

the presecne of a lattice means we have antibody and antigen

the presencce of a button means only antigen

the zone of equivalence is where these signs will show

Question 23

using aglutination we can see how the valncy of antibodies and antigens are improatnt. Describe some examples

Answer 23

univalent antigen + antibody = no cross linking

multivalent antigen + antibody = cross linking

multivalent antigen + only Fab region of antibody = no cross linking

multivalent antigen + (Fab)2 antibody = cross linking

Question 24

how is the DNA ligand identifiable

Answer 24

when antibody and antigen interact it forms a triangle

Question 25

what are the biological consequences to Ag binding

Answer 25

1) virus neutralization - prevents pathogen binding

2) opsonization - lead to pahgocytosis

3) complement fixation and formation of the membrane attack complexes - (holes in membrane) leads to phagocytosis or lysis

4) antibody -dependent cell mediated cytotoxicity (ADCC) - Ig binds to infected cells or tumors and then NK comes and kill them so NK induced apoptosis

5) transcytosis - moving the Ab accross the epthiptheal layer (placenta)

Question 26

what is virus neutralization

Answer 26

Ab binding blocks binding of toxin or virus to cell

Question 27

what is oponsisation

Answer 27

promotes phagocytosis of Ag via interaction with Ab

Question 28

what is activation of complemtns?

Answer 28

directky destroys cells

Question 29

what is ADCC?

Answer 29

killing by NK cells

Question 30

what is transcytosis?

Answer 30

moving the Ab accross the epthiptheal layer (placenta)

Question 31

whihc of the 5 consquences of Ag binding is not mediated by the Fc region of antibody?

Answer 31

neutralization of viruses