VMC 221: Veterinary Immunology and Serology (1+1)

PROCEDURE

• Add 25 μl of normal saline in all the wells.
• Add 25 μl of the serum in the first well and make serial two-fold dilution. Discard 25 μl  of the suspension from the last well.
• Add 25 μl of virus suspension containing 4 HA units to all the wells. Leave for 30 minutes at room temperature.
• Add 25 μl of 1% chicken RBC to all the wells and leave for 40 minutes.
• RBC control: Add 25 μl of saline to a well to which add 25 μl of 1% chicken RBC.
• Check titration: - Add 25 μl of saline to 4 wells in a row. Add 25 μl of the 4 HA virus suspension to the first well and make serial tow-fold dilution. Discard 25 μl of the suspension from the fourth well. Add 25 μl of 1% chicken RBC to all the four wells. Leave for 30 minutes. The first two wells will show haemagglutination if the viral suspension prepared is having 4HA units of virus in 25 μl.
• The end point or Hl titre of the serum is the reciprocal of the highest dilution showing 100% inhibition of haemagglutination.

In this figure HI titre = 64(2⁶)

This test can be used for the estimation of antibody level againsted Newcastle disease virus.