Ab/ag Reactions

Front 1

Recall the two classes of antibody routinely detected in the blood bank laboratory and state the optimal temperature at which each reacts in vitro

Back 1

IgM-reacts best at 4-22
IgG-reacts best at 37

Front 2

Indicate the number of antigen binding sites on each of the atnibody classes routinely detected in blood banking

Back 2

IgM-10
IgG-2

Front 3

What type of environment does IgG react best?

Back 3

a high protein environment

Front 4

Name and describe the two stages of an agglutination reaction.

Back 4

1. Sensitization-the binding of antigen and antibody
2. Lattice formation-visible agglutination

Front 5

Explain how the following factors influences sensitization: Concentration of antigen, concentration of antibody, pH of the medium, temp, ionic strength of the medium

Back 5

1. Increasing the number of Ag increases the amount of complexes but there are fewer Ab/cell so the rxn is not visible
2. Increase Ab increases Ab/cell so reaction can be seen.(beware of prozone)
3.Optimal activity correlates with physiologic pH
4.IgG-37, IgM-4-22
5.LISS reduces the concentration of ions in the test which enhances sensitization

Front 6

Define and explain Zeta potential

Back 6

-The electrostatic potential measured between the red cell membrane and the slipping plane ofr the same cell.
-If you can decrease the thickness of the cloud you can enhance agglutination

Front 7

Discuss the following factors as they relate to agglutination of red blood cells: ZP, enzyme treatment of red cells, dielectric constant(albumin)

Back 7

1. RBCs are = charged, cations from the saline are attracted to the = charge resulting in a fixed + cloud surrounding each cell repelling adjacent, similarly charged cells.
2.Treating RBC's with proteolytic enzymes allows them to become less negative, but can destroy some antigens(not routinely used)
3.Albumin decreases ZP by increaseing the dielectric constant of the medium(dissipates charges)

Front 8

List and explain three methods that may be used to decrease the zeta potential an enhance agglutination.

Back 8

Albumin(dissipates charges)
Enzymes(decreases negativity of RBCs)
Centrifugation(forces cells together)

Front 9

Define "LISS" and describe how it is used in the BB lab

Back 9

1. Low Ionic Strength Saline reduces the concentration of ions in the test. IgGs dont react well in vitro, but will react well at body temp. LISS enhances sensitization.

Front 10

Define complement

Back 10

a group of naturally-occuring serum protiens that interact with some Ag-Ab complexes in a sequential manner to irreversibly damage the cell membrane and lyse the cell

Front 11

Explain the role of ionic Ca and Mg in complement activation

Back 11

act as stabilizers

Front 12

Describe the relationship between the activation of complement and Ag-Ab reactions

Back 12

The classical pathway is triggered by an Ag-Ab reaction.

Front 13

Explain the function of complement proteins in vivo

Back 13

Lysing of cells-bacteria, enveloped viruses, foreign RBC's

Front 14

Describe how complement proteins are used in vitro

Back 14

Detection of complement protiens on the surface of and RBC may be the only indication that an Ag-Ab reaction has occured