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Practical Basic Microbiology and Immunology (Clinical Program) LAB #6_Serology

Practical Basic Microbiology and Immunology (Clinical Program) LAB #6_Serology. Serology: In vitro Antigen- Antibody reactions. Antigen- Antibody reactions are classified according to the physical state of antigen into:. Blood grouping (hemagglutination reactions).

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Practical Basic Microbiology and Immunology (Clinical Program) LAB #6_Serology

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  1. Practical Basic Microbiology and Immunology (Clinical Program)LAB #6_Serology

  2. Serology: In vitro Antigen- Antibody reactions • Antigen- Antibody reactions are classified according to the physical state of antigen into:

  3. Blood grouping (hemagglutination reactions) • Hemagglutination reactions are used in typing of blood • According to the presence of 2 surface antigens (A, B) on red blood cells, there are 4 combinations of these antigens giving 4 different blood groups: A, B, AB,O • Another surface antigen exist on human RBCS Rh factor or D antigen • Accordingly, individuals are either Rh-positive or Rh- negative

  4. Procedure Anti-A Anti-B Anti-D • A person’ s blood group is determined by mixing 3 separate drops of blood on a slide with Anti A serum - Anti B serum – Anti D serum • After mixing each square with separate toothpicks, look for agglutination

  5. Questions: • Type of serological reaction: Hemagglutination reaction • Blood group is ……..

  6. Complement fixation test (CF tests) • Can be used for both antigen or antibody detection. • Example for screening of syphilis • Complement proteins are usually found in an inactive form. • Once activated, they become involved in a chemical cascade • It is the cell- lysing ability of activated complement components that is important in CF tests

  7. Press here for video https://drive.google.com/a/pharma.cu.edu.eg/file/d/0B8qHsBaYOFwUZ2M1U1dXTWI2VDg/edit?usp=sharing

  8. Principle • The complement fixation tests depend upon 2 distinct systems: • Test system • involves Ag and Ab (one of which is known, the other is unknown) +complement • If Ag and Ab are specific for one another, they will combine and fix the added complement • Indicator system • sensitized sheep RBCsis used as an indicator system to test for the presence of free complement.

  9. Principle • If the complement has been fixed by Ag-Ab complex, none will be available for lysis of sensitized sheep RBCs. • If Ag and Ab are not specific for each other (or no antibody present), the complement remains free to attach to sensitized sheep RBCs and lyse them ∴ a positive complement fixation test gives no hemolysis AND a negative test gives hemolysis

  10. Positive Complement Fixation Negative Complement Fixation

  11. Titer: reciprocal of the highest dilution (or least concentration) of antibody which gives a positive result Titer = 4

  12. Results • Positive Complement Fixation: • all tubes show no hemolysis (opaque), except control tube Control

  13. Results • Positive Complement Fixation with Titer

  14. Results • Negative Complement Fixation • all tubes show hemolysis including control tube

  15. Results • Anti Complementary Reaction • control tube shows no hemolysis, indicating that something is wrong in the test or indicator system, preventing lysis of RBCs

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