2) Haemagglutination Inhibition Assay:

In addition to titrating virus preparations, this varion of the haemagglutination assay can also be used to determine the antigenic type of the virus. Haemagglutination will not occur in the presence of antibodies which bind to and block the virus haemagglutinin. The minimum amount of virus which will cause haemagglutination of all the RBC's in a well is known as one haemagglutinating unit (HAU). If an antiserum is titrated against a given number of HAU, the haemagglutination inhibition (HAI) titre and specificity of the antiserum can be determined. Also, if antisera of known specificity are used to inhibit haemagglutination, the antigenic type of an unknown virus can be determined. This is the second part of the experiment you will perform.

You are provided with the following solutions:
  • Phosphate buffered saline (as before)
  • Influenza virus stock of unknown type, 8 HAU/50µl
  • 0.5% RBCs in PBS (as above)
  • Reference antisera: (Antigenic type):
    1. A/H1N1
    2. A/H2N2
    3. A/H3N3

Set up the plate

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