Neutralization Test

Neutralization Test
1. Antibody or Antigen activity tested through sequential dilution until activity ceases
2. Activity test examples include Infectivity in tissue culture, Hemolysis or Agglutination

Plaque Reduction Neutralization Test (PRNT)
1. Patient serum sample at sequential dilutions added to known virus sample and then incubated
2. Solution of serum and virus are poured over a single layer of host cells and covered with agar
3. Concentration of infected cell regions (Plaques) are then measured over several days
Complement Fixation Test
1. Patient serum sample at sequential dilutions added to known virus sample
  1. Antigen-Antibody complexes form if Antibody to the specific virus is present
2. Test solution contains complement and RBCs (e.g. sheep RBCs) coated with hemolysin
3. Serum-virus solution is added to the complement-RBC test solution
  1. Hemolysis occurs if Antigen-Antibody complexes were present to activate complement
  2. Hemolysis will not occur if the specific Antiviral Antibody is absent from the patient's serum
Antistreptolysin O Titer (ASO Titer)
1. ASO Titer is now performed as an Agglutination Test, but was previously a Neutralization Test
2. Streptococcus produces streptolysin O which causes Hemolysis
3. Test starts by combining streptolysin O with sequential dilutions of patient serum
4. Human RBCs are added to streptolysin O and serum mix
5. Antistreptolysin Antibody will neutralize the streptolysin and prevent Hemolysis
6. Maximal serum dilution that still prevents Hemolysis will result in an ASO Titer