Serological test for virus identification

This presentation consist of detailed study of serological method of virus identification. Basically ELISA is vastly used for virus detection. Western blot method is used for HIV identification.

1. SEROLOGICAL DIAGNOSIS OF VIRAL INFECTIONS: POSSIBILITIES OF SEROLOGICAL DIAGNOSIS TYPES OF SEROLOGICAL REACTIONS Presentation on

2. Presented By Sulove Kumar Ghosh Student ID: MS-190807 Plant Pathology Agrotechnology Discipline Khulna University

3. Introduction Serological methods are diagnostic methods that are used to identify antibodies and antigens in patients sample which is serum and plasma . A serological diagnosis is prepared by detecting the rising titres of antibody or antigens By serological methods most of the common viral infections are diagonized .

4. Historical Development 1798 - First demonstration of vaccination smallpox vaccination (Edward Jenner ) 1890 - Demonstration of antibody activity against diphtheria and tetanus toxins. 1900 - Antibody formation theory (Paul Ehrlich ) 1938 - Antigen-Antibody binding hypothesis (John Marrack ) 1948 - antibody production in plasma B cells

5. Historical Development 1959 -1962 - Discovery of antibody structure Enzyme Linked ImmunoSorbent Assay {ELISA} 1971 - Peter Perlmann and Eva Engvall at Stockholm University invented ELISA 1975 - Generation of the first monoclonal antibodies ( George Kohler and Cesar Milstein ) 1978- Used ELISA for plant virus identification 1985- Identification of immunoglobulin gens

6. SEROLOGICAL REACTIONS SEROLOGICAL REACTIONS Ag-Ab reactions used for the detection of unknown Ag or Ab, in vitro In virology: Viral (direct) diagnosis : detection of viral antigens Serological (indirect) diagnosis : detection of specific antiviral antibodies

7. Qualitative detection of total specific antiviral antibodies Quantification of total specific antiviral antibodies (titer of Abs) 1/2 1/4 1/8 1/16 1/32 1/64 POSSIBILITIES OF SEROLOGICAL DIAGNOSIS POSSIBILITIES OF SEROLOGICAL DIAGNOSIS

8. Detection of Ab classes (qualitative and quantitative) POSSIBILITIES OF SEROLOGICAL DIAGNOSIS POSSIBILITIES OF SEROLOGICAL DIAGNOSIS

9. Detection of Ab synthetized to each viral protein (Ag) of specific molecular weight – serological profile POSSIBILITIES OF SEROLOGICAL DIAGNOSIS POSSIBILITIES OF SEROLOGICAL DIAGNOSIS

10. Determination of specific antibody avidity POSSIBILITIES OF SEROLOGICAL DIAGNOSIS POSSIBILITIES OF SEROLOGICAL DIAGNOSIS

11. C l a s s i c a l M o d e r n Types of serological reactions Types of serological reactions – detection of Ab that block biological functions of the virus Neutralization test Haemagglutination Inhibition Test – based on biological activity of Abs in complex with Ags Immunoagglutination Complement Fixation Test (CFT) – based on application of labeled antibodies EIA (ELISA) I m m u n o f l u o r e s c e n c e RIA – determination of serological profile Western blot

12. based on application of labeled antibodies ELISA – Enzyme Linked ImmunoSorbent Assay Microtiter Plate(96)

13. Different types of ELISA

14. E L I SA

15. Advantages of ELISA Reagents are relatively cheap & have a long shelf life ELISA is highly specific and sensitive No radiation hazards occur during labelling or disposal of waste. Easy to perform and quick procedures Equipment can be inexpensive and widely available. ELISA can be used to a variety of infections.

16. Disa d va n tages of ELI S A Measurement of enzyme activity can be more complex than measurement of activity of some type of radioisotopes. Enzyme activity may be affected by plasma constituents . Kits are commercially available, but not cheap Very specific to a particular antigen. Won’t recognize any other antigen False positives/negatives possible, especially with mutated/altered antigen

17. Limitations Results may not be absolute Antibody must be available Concentration may be unclear

18. determination of serological profile Western blot as serological reaction: confirmation test ( H I V ) Serological profile – presence of Ab specific for different viral Ag

19. Western Blot for HIV HIV-1 Western Blot Lane1: Positive Control Lane 2: Negative Control Sample A: Negative Sample B: Indeterminate Sample C: Positive At least 1 Ab for products of all 3 major genes ( 3 ) (CDC) Two Ab for any of the 3 major Ag: p24, gp41, gp120/160 ( 2 ) 3 genes: - G AG - POL - ENV POSITIVE

20. THANKS TO ALL