Abstract: Rabbit anti-H9N2 subtype avian influenza virus (AIV) serum was purified by protein G affinity chromatograph,caprylic acid-ammonium sulfate precipitation and saturated ammonium sulfate precipitation separately. It was found that the antibodies obtained from the first method was of the highest purity,unchanged activity,relatively low recovery rate,easy operation and high cost,which indicated that the first method was suitable for laboratory studies and purification in small sample volume. Antibodies obtained with the second method were of lower purity than that from the first method and of unchanged activity. Repeated salting out could improve the purity. It was suitable for preliminary purification before protein G affinity chromatograph. The third method was often used in crude extraction in large volume samples or the purification of ascitic fluid. With this method,purity of the antibodies obtained was lower than that from the other two methods,recovery rate was high and activity of antibodies unchanged. The purification demanded for relatively high accuracy of pH value and caprylic acid concentration.

Key words: purification methods; H9N2 subtype AIV; serum