Antigen receptor genes

Question 1

what is the issue of inheritance of DNA

Answer 1

most genes have a maternal and paternal form

the issue is that But B cells are clonal: one
B cell produce only 1 Ab
e.g. monoclonal Ab production

Issue 2. There is no limit to the number of
antigens that can be recognized by B cells

Question 2

what is the solution to the monoclonal gene problem

Answer 2

So how can the immune system do this?
- have multiple genes
- ”re-use” the same genes

Question 3

who performed the paradigm shifting experiment

Answer 3

hozumi and tonegawa

Question 4

what are antibodies

Answer 4

Proteins made by B cells that bind antigen

Question 5

what are the similarities and differences between secreted and membrane ig

Answer 5

they have the same Fab but a different C-terminus

Question 6

Antibodies interact with Ag at

Answer 6

Complementarity-
determining regions (CDR)

Question 7

what are CDRs

Answer 7

CDRs are the loops in the Fab region, the rest is called the framework regions

Question 8

mithridatism

Answer 8

Protection against poisoning observed in response to small doses of
poisons
* Mithridatism – Mithradates VI, Greece, 135-63 BC
* Practice was thought to have saved Rasputin from being killed with poison

Question 9

diptheria protection

Answer 9

1880-90s- Emil von Behring; protection against diptheria toxin is
found in the serum of animals if injected with non-lethal heat-treated
toxin (also tetanus)

Question 10

what bacteria produce the diptheria and tetanus toxin

Answer 10

Toxins produced by bacteria: Corynebacterium diphtheriae and Clostridium
tetani, respectively

Question 11

diptheria stats

Answer 11

Diptheria: Death rate: 5-10% (20% if <5 years or >40 years old), 1930’s – one
of top 3 causes of death in children

Question 12

tetanus symptoms and antitoxin

Answer 12

• Tetanus: lockjaw, no natural immunity is acquired after natural exposure
• Antitoxin: inject non-lethal diptheria and tetanus toxin into horses and obtain
  serum

Question 13

what is the process for isolation and discovery of antibodies

Answer 13

• Serum is isolated from rabbits that have
  been injected with Ovalbumin
• Electrophoresis separates proteins by charge
  and mass
• Black line shows serum that has been pre-
  incubated with Ovalbumin (the antigen)
• Antibodies (Ab)= Immunoglobulin (Ig)

Question 14

what do agglutination reactions do

Answer 14

demonstrate that Ab
are substances

Using
agglutination as
the read-out, it is
clear that the
“valency” of
antibodies and
antigens is
important

Question 15

biological consequences of Ab binding

Answer 15

neutralization
opsonization
activation of complement
antibody depended cell mediated cytotoxicity (ADCC)
granule release
transcytosis

Question 16

neutralization

Answer 16

Ab binding blocks binding of toxin or virus to cell

Question 17

opsonization

Answer 17

promotes phagocytosis of Ag via interaction with Ab

Question 18

activation of complement

Answer 18

directly destroys cells

Question 19

Antibody-dependent cell-mediated cytotoxicity (ADCC)

Answer 19

killing
by NK cells

Question 20

granule release

Answer 20

release of granules into the extracellular space

Question 21

transcytosis

Answer 21

Moving Ab across epithelial layers (ie. placenta)

Question 22

generation of Ab diversity occurs in

Answer 22

the bone marrow independent of Ag

Question 23

Examining the DNA sequences of light chain reveals

Answer 23

the use of different ’V’ regions but the
same ‘C’ region

Question 24

the same Ch or Cl region can be connected to

Answer 24

millions of different Vh or Vl regions

Question 25

myeloma

Answer 25

plasma cell cancer
* secrete all of the same Ig or just IgL
(light chain)
* When just IgL called Bence Jones
proteins

Question 26

2 types of light chain

Answer 26

Lambda
Kappa
X 2 parents
= 4 possible C gene alleles