Immunologic assays

Question 1

What is a “passive protection test” (ED50)?

Answer 1

• test of vaccine efficacy
• serum from vaccinated individuals injected into animal
• animal challenged with infectious agent
• highest dilution of serum that protects 50% of animals is the (ED50) efficacy of vaccine

Question 2

What is an “active protection test” (LD50)?

Answer 2

• animals are vaccinated
• challenged with infectious agent
• lowest # of microorganisms that are lethal for 50% of animals (LD50) compared to LD50 in non-vaccinated animals to determine efficacy

Question 3

What is an agglutination test used for?

Answer 3

• identification the presence of bacteria (non-quantitative and non-specific)
• diagnosis - addition of suspect bacteria, highest dilution that results in agglutination is called a TITER. 4Xtiter is significant for diagnosis.

Question 4

What is a slide agglutination test?

Answer 4

• Used in blood grouping to determine whether a donor’s serum or cells possess antigens or antibodies that are reactive with the recipient’s serum or cells

Question 5

Major crossmatch/minor crossmatch in agglutination testing

Answer 5

major crossmatch: Donor cells and recipient serum. Rapid clumping of donor cells means anti-RBC antibodies present in recipient serum
minor crossmatch: Donor serum and recipient cells. Same idea but not as much of a concern because donor serum will be diluted