9. Readings The results
Titer: The maximum dilution that gives visible agglutination.
The end point: is the well with the lowest concentration of the
virus where there is haemagglutination
Titer dilution contains (1 HA unit) (one haemagglutinating
unit)
10. In the absence of anti-virus antibodies
Erythrocytes
Virus
Virus agglutination of
erythrocytes
12. Viral Haemagglutination Inhibition
Tests
The presence of virus can be detected by hemagglutination
The identity of the virus or of antibodies in a patient’s serum
can be determined by specific inhibition of that
hemagglutination
14. In the presence of anti-virus antibodies
Erythrocytes
Virus Anti-virus
antibodies
Viruses unable to bind to
the erythrocytes
15. Significance
Useful for viruses that are not cytopathic
Based on viral hemagglutination
Some viral surface proteins can clump red blood cells
A serum sample that contains antibodies against a specific virus will
inhibit viral Haemagglutination
Commonly used to detect antibodies against influenza, measles, and
mumps
17. Complement system
A part of the immune system that enhances (complements)
• the ability of antibodies and phagocytic cells to clear microbes and damaged cells
from an organism
• promotes inflammation
• attacks the pathogen's plasma membrane.
or
A system of plasma proteins
can be activated directly by pathogens or indirectly by pathogen-bound antibody,
leading to a cascade of reactions that occurs on the surface of pathogens and
generates active components with various effector functions.
18.
19. Complement fixation test
Complex assay used to detect the presence of specific antibodies in
an individual's serum.
The test can detect the presence of small amounts of antibody---
amounts too small to detect by agglutination
Principle
It is the nature of the complement to be activated when there is formation
of antigen-antibody complex.
20.
21. Results
In the positive test : The available complement is fixed by Ag-Ab
complex and no haemolysis of sheep RBCs occurs. So the test is
positive for presence of antibodies.
In the negative test : No Ag-Ab reaction occurs and the complement is
free. This free complement binds to the complex of sheep RBC and it’s
antibody to cause haemolysis, causing the development of pink colour.
23. Immunodiffusion
Definition
It is a simple and direct means of demonstrating the Ag-Ab by the
precipitation reaction (Ag and Ab are soluble)
o Radial Immunodiffusion (Mancini method).
o Double Immunodiffusion
24. Radial immunodiffusion assay
also known as the Mancini method
A protein assay that detects the amount of specific viral antigen
The medium contains antiserum specific to the antigen of interest and the antigen
is placed in the well cut into agarose gel
The Ags (in the serum) diffuses radially and produces a ring of precipitation.
The area enclosed by the ring is proportional to the conc. of the Ag in the serum
25.
26. Double Immunodiffusion
In double I.D both reactants are free to move towards each
other and Precipitate
Movement in either form may be linear or radial
27. The density of the line reflects the amount of immune complexes formed
28. Immuno-electrophoresis
Double-diffusion technique that utilizes electric current to enhance results.
Immunoelectrophoresis is a qualitative method that combines
electrophoresis and immunoprecipitation.
Electrophoresis separates molecules according to differences in their electrical charge
and their sizes.
29. Principle
Antigen from
serum
electrophoresed
Trough is cut
in the gel
parallel to the
line of
separation
Antiserum is
placed in the
trough
Incubate: 18-
24 hours
•double diffusion
occurs at right
angles to the
electrophoresis
separation
•Precipitin lines
develop where
Ag-Ab
combination takes
place.
Lines or arcs shape, intensity and
location: compared with normal
serum control
2 step process
30.
31.
32. Uses
to identify different disease entities
to aid in monitoring the course of the disease
therapeutic response of the patient with such conditions as
immune deficiencies, autoimmune disease, chronic infections,
chronic viral infections etc.
33. MCQs
One principal function of complement is to
A. inactivate perforins
B. mediate the release of histamine
C.Bind antibodies attached to cell surfaces and to lyse these cells
D.phagocytize antigens E. cross link allergens
34. MCQs
One principal function of complement is to
A. inactivate perforins
B. mediate the release of histamine
C. Bind antibodies attached to cell surfaces and to lyse these cells
D. phagocytize antigens E. cross link allergens
35. MCQs
Antigen-antibody reactions can result in the following:
A. Agglutination
B. complement fixation
C. Precipitation
D. All of the above
36. MCQs
Antigen-antibody reactions can result in the following:
A. Agglutination
B. complement fixation
C. Precipitation
D. All of the above
37. MCQs
The double diffusion method allows for disease identification and diagnosis
and is an application of what immunological technique?
A. Agglutination
B. Precipitation
C. Immunoassay
D. Fluorescent antibody test
E. Complement fixation
38. MCQs
The double diffusion method allows for disease identification and diagnosis
and is an application of what immunological technique?
A. Agglutination
B. Precipitation
C. Immunoassay
D. Fluorescent antibody test
E. Complement fixation
