BB Basics 2 Flashcards
Antigen antibody type of reaction and what is binding
Lock and Key mechanism. Antibody binds to an epitope on immunogen
Affinity
Strength of a single antibody-antigen bond determined by the sum of attractive and repulsive forces
Avidity
Binding strength of a multivalent antigen with antibody. Measure of functional affinity
What needs to happen in order for chimerism to occur
Twins must be dizogotic, share an amniotic sac and a blood vessel
What does an EDTA tube chelate
Ca++
What happens in a clot tube
Ca++ is free and the complement cascade can still be active
Antibody excess zone
Prozone - leads to false negatives
Antigen excess
Postzone - can lead to false negatives
The right antigen antibody concentration zone
Zone of equivalence
What does centrifugation do
Brings reactants closer together to overcome zeta potential. Also decreases reaction time
Zeta potential theory
Difference in charge of an ionic cloud that surrounds an RBC causes cells to stay apart or repel
Ideal pH for ag-ab reaction
6.5-7.5
Antibodies that like to react at pH lower than 6.5
M and Pr
Ideal reaction temperature for IgM
22C or below
Ideal reaction temperature for IgG
37 and AHG
Number of IgM binding sites and how much more efficient it is at agglutinating
10 sites. 750 times more efficient
Ideal time to read a reaction (curve)
During the high association low dissociation log phase
Steps in agglutination
Sensitization-> Lattice formation-> Agglutination.
In IgM the first 2 can happen at the same time
Steps in agglutination when adding IgG
Sensitization->Opsonization->AHG->Lattice formation
How are polyclonal vs monoclonal reagents made
Polyclonal - animals injected
Monoclonal - hybridoma cells
Hybridoma cell
Cancer cell that continues to replicate, allows plasma cell to survive a long time
How does AHG work
Fab region of AHG binds to Fc region of already bound IgG
What does a DAT detect
In-vivo coating of RBCs
What type of tube should be used for a DAT
EDTA. Clot tubes may give a false positive C3 result
