What is viral hemagglutination inhibition test?
The hemagglutination inhibition (HI) assay is used to titrate the antibody response to a viral infection. The HI assay takes advantage of some viruses’ ability to hemagglutinate (bind) red blood cells, therefore forming a “lattice” and preventing the red blood cells from clumping.
What is the principle of haemagglutination test?
The principle behind the hemagglutination test is that the nucleic acids of viruses encode proteins, such as hemagglutinin, that are expressed on the surface of the virus (Figs. 51.1 and 51.3).
What is a positive hemagglutination test?
Positive control allantoic fluid is known to contain a high infectivity titre of Newcastle disease virus. It should always test positive for the presence of haemagglutinins. Haemagglutination should be visible. This test can determine the presence of a haemagglutinating agent in one minute.
What is the haemagglutination used for in the study of virus?
Hemagglutination is used for the diagnosis of some enveloped viruses such as influenza viruses. This method relies on the specific feature of some enveloped viruses that can adsorb to red blood cells (RBCs). Specifically, hemagglutinin5 (HA), an envelope glycoprotein of some enveloped viruses, imparts this property.
What causes hemagglutination?
Hemagglutination is a reaction that causes clumping of red blood cells in presence of some enveloped viruses, such as the influenza virus. A glycoprotein on the viral surface, namely hemagglutinin, interacts with red blood cells, leading to the clumping of red blood cells and the formation of a lattice.
What is viral hemagglutination?
What is hemagglutination activity?
Hemagglutination, or haemagglutination, is a specific form of agglutination that involves red blood cells (RBCs). It has two common uses in the laboratory: blood typing and the quantification of virus dilutions in a haemagglutination assay.
Which viruses can cause hemagglutination?
Why do viruses cause hemagglutination?
During the incubation, antibodies bind to the viral particles, and if the concentration and binding affinity of the antibodies are high enough, the viral particles are effectively blocked from causing hemagglutination.
What is agglutination and hemagglutination?
Agglutination is defined as the formation of clumps of cells or inert particles by specific antibodies to surface antigenic components (direct agglutination) or to antigenic components adsorbed or chemically coupled to red cells or inert particles (passive hemagglutination and passive agglutination, respectively).
How will you confirm clumping of red cells?
Serum electrophoresis showed a small IgM “M” component. The recognition of the clumped red cells prompted the physician to cool the blood sample, and another smear was made. The warmer (room temperature) blood is shown on the top right and the slide of the chilled blood is on the bottom right.
How is hemagglutination used to detect a virus?
Hemagglutination inhibition assay (HIA) is used to detect and titrate antibodies developed against a virus. In HIA, an absence of hemagglutination is observed to detect the presence of antibodies in a given sample. Mechanistically, virus-containing samples are incubated with serially-diluted serum samples.
How is the hemagglutination inhibition ( HI ) assay used?
Hemagglutination-inhibition (HI) assay is a classical laboratory procedure for the classification or subtyping of hemagglutinating viruses. For influenza virus, HI assay is used to identify the hemagglutinin (HA) subtype of an unknown isolate or the HA subtype specificity of antibodies to influenza …
What’s the best way to test for hemagglutination?
Add a fixed amount of virus to every well of a 96-well plate, equivalent to 4 HA units (varies according to the virus), except for the serum control wells. Allow the plate to stand at room temperature for 60 minutes (time varies according to specific requirements). Add red blood cells (RBC) and incubate at 4°C for 30 minutes. Read the wells.
Why does the Hai test not show hemagglutination?
Likewise, if antibodies to the measles virus are present, hemagglutination will not be observed until the antibodies are sufficiently diluted. The HAI test may be complicated by the presence of non-specific inhibitors of viral haemagglutination and naturally occurring agglutinins of the erythrocytes.