1986 Volume 48 Issue 6 Pages 1141-1146
The mechanism of suppression of plaque formation of infectious bursal disease virus (IBDV) by calf serum (CS) was investigated. Suppressor in CS was absorbed by incubation of the serum with chicken embryo fibroblast (CEF), indicating the attachment of suppressor to CEF. The amount of IBDV that was able to absorb to CEF decreased when the cells were pretreated with CS. Suppression of IBDV plaque formation was also noted when CS was added to agar overlay medium, indicating that the serum suppressed the spread of the virus infection to the surrounding cells. The suppressive effect of CS was not due to a direct inactivation (neutralization) of IBDV. The results indicated that the suppressor in CS attaches to the surface of CEF and probably occupies the virus receptors on the cells, therefore blocking the absorption of the IBDV and consequently, leading to the suppression of plaque formation by the virus.
