Hemagglutination (HA) reaction with purified cytoplasmic-polyhedrosis virus (CPV) of the silkworm was investigated by the use of some mammalian erythrocytes. The results obtained are as follows:
1. Purified CPV and CPV-infected midgut homogenate hemagglutinated chicken erythrocytes, but healthy midgut homogenate did not.
2. When several concentrations of a chicken erythrocyte suspension in saline were mixed with an equal amount of the virus suspension in 0.01M phosphate buffered saline (pH6.8), 0.4-0.5% erythrocyte suspensions always gave the best results.
3. When 4, 25 and 35°C were used for the reaction temperature, the most suitable result was obtained at 4°C.
4. The stable pH range of the reaction was between 5.5 and 8.6 at 4°C in phosphate buffered saline, and the minimum quality of the virus detectable was 4-12μg/ml.
5. CPV hemagglutinated chicken, sheep and mouse erythrocytes, and the chicken erythrocyte was the most sensitive among them.
6. The HA value of CPV decreased gradually when CPV was kept at 4°C for more than two days.
7. When CPV was treated with ether, Tween 80-ether, sodium desoxycholate, fluorocarbon (once), formalin or hot water (90°C, 10min.), UV (40min.), the HA value was not affected.
8. Hemagglutination inhibition (HI) reaction was positive on CPV.