Antibody Genes

Question 1

Define DNA recombination

Answer 1

Changing the relative positions of 2 pieces of DNA

Question 2

Define RNA transcript

Answer 2

a

Question 3

Define RNA splicing

Answer 3

a

Question 4

Define somatic mutation

Answer 4

a

Question 5

Define antibody affinity maturation

Answer 5

a

Question 6

Define toxoid

Answer 6

Bacterial toxin (usually an exotoxin)

Toxicity has been weakened/suppressed through chemical (e.g. formalin) or heat treatment —> vaccines

Think: tetanus toxoid!

Question 7

Define cross reactivity

Answer 7

The tendency of one Ab to react with more than one Ag

Question 8

What is an example of a non-self antigen which cross-reacts with a self antigen?

Answer 8

Immunizing a person with cow pox, the antigenic determinants of small pox will also be recognized

Person now immunized

Question 9

What is instructional theory as it relates to immunology?

Answer 9

• Old theory, shown to be wrong
• Ag told immune system in some way to make Abs in specific conformation
• A Lamarckian theory b/c it implied outside world instructed the cell to change genetic info

Question 10

What is Clonal Selection Theory?

Answer 10

• Each immune cell is programmed to make only one Ab
• That Ab is totally RANDOM
• Not dependent on outside information (Ab genetic code preexists before contact with Ags)
• A Darwinian theory —> survival of the fittingest

Question 11

What is the process explained by Clonal Selection Theory?

Answer 11

• New Ag in body —> contacts lymphocytes
• When it finds one whose receptors bind with high affinity, lymphocyte is activated
• Moral of the story: the best fitting clones are selected by Ag

Question 12

What experiment proves the Clonal Selection Theory?

Answer 12

• Ag X w/ radioactive label (all cells bound to it will die)
• Only pre-existing cells bind to this label (rather than all as said in instructional theory)
• Animal then immunized w/ nonradio-X, and Y
• Response to Y, but not X