Purification of recombinant 38-kDa phosphorylated protein of Marek's disease virus from insect cells through an affinity column.

The 38-kDa phosphorylated protein (pp38) of Marek's disease virus (MDV) expressed in insect cell line Sf9 cells infected with recombinant baculovirus BP38II was purified through an affinity column made of CNBr-Sepharose 4B linked with monoclonal antibody (Mab) H19 specific to serotype I MDV. The result of SDS-PAGE showed a main band of 38 kDa in the lane loaded with the purified pp38, and this band was specifically recognized by MAb H19 in Western blot. The serum from mice immunized with the purified recombinant pp38 reacted only to Sf9 cells infected with the recombinant baculovirus BP38II but not with wild baculovirus. It also gave a titer of 1:128 in indirect fluorescence antibody test to MDV-infected chick embryo fibroblast cells. These results indicated that the purification procedure was effective and that it would be useful for investigating the biological functions of MDV pp38.