The viral neutralization test is a serological method that detects the presence of viral neutralizing antibodies. It involves mixing dilutions of antibodies with a standardized amount of virus, incubating them, and observing for cytopathic effects in cell cultures. If the antibodies neutralize the virus, no cytopathic effects will be observed as the cells remain intact. While the viral neutralization test is highly sensitive and specific, it is also slow, intensive, and requires skilled technicians. It remains the gold standard method for diagnosing viral infections in the laboratory by comparing other test methods to it.

1. VIRUS
NEUTRALIZATION
TEST
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2. VIRUS NEUTRALIZATION
TEST
Introduction
 Serological method that detects the presence of viral
neutralizing antibodies.
 The antibodies bind to the viral particles
• Monoclonal and polyclonal antibodies
 Block viral infectivity-No cell infection
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3. VNT cont..,
 VNT are conducted by :
 mixing dilutions of antibodies with standardized amount of
virus, incubating them and cultured into cells, eggs or animals
to have a clear cytopathic effect observation
 CPE effects:
 Rounding of cells
 Change in texture-granular/hyaline/glassy
 Formation of syncytium
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4. VNT cont..,
 STEPS
• First step:
• Serial dilutions of serum(virus-neutralizing Ab?)+ known virus
• Incubated for 1-2hr at 37 degrees Celsius
• Second step;
• Cell culture inoculated with mixture
• Seal the plates & Incubated at 37 degrees Celsius
• Direct microscope
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5. VNT cont.,
• Illustrations using diagrams
Copyright 2009, John Wiley & Sons, Inc.
Copyright 2009, John Wiley & Sons, Inc.
Copyright 2009, John Wiley & Sons, Inc..
right 2009, John Wiley & Sons, Inc.
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6. VNT cont..,
• Expectations
• No Ab(in serum)+virus no neutralization
CPE
• Ab(in serum)+virus neutralization No CPE
• Cells remain intact
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7. VNT cont..,
-pro’s:
• Can be specific
• Sensitive
• Vaccine production/immunological studies
-con’s:
• Very slow(days)
• Intensive
• Require skilled people
• Depend on cell line-use of wrong cell lines may assume that the
antibodies have neutralization ability when not, or may seem to
be ineffective when they actually have the neutralization abilities.
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8. Conclusion
All in All, viral infections can be diagnosed in
laboratory by many methods and the gold
standard one is neutralization tests since it is a
technique to which all other test methods have
been compared with. Although the technique is
highly sensitive and specific in detection of
antibodies, it has disadvantages.
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9. REFERENCES
1) Carter,J.,and
Saunders,V.(2007).Virology:Principles and
Applications.John Willey & Sons,Ltd.England,UK.
2) Flint,S.J.,Enquist,L.W.,Racaniello,V.R.,and
Skalka,A.M.(2004).Principles of virology:Molecular
Biology,Pathogenesis and Control of Animal
Viruses.2nd Edition.ASM press,Washington
DC,USA.
3) Murphy, F.A.,Gibss ,J.P.,Horzinek.M.C.,and
Studdert,M.J.(1999).Veterinary Virology.2nd
edition.Elsevier,Inc.Califonia,USA.
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10. THANKS FOR YOUR ATTENTION
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