Increased virulence of Marek's disease virus type 1 vaccine strain CV1988 after adaptation to qt35 cells.

CVI988/Rispens strain of Marek's disease virus type I (MDV-1) is widely used as efficient vaccine to control Marek's disease (MD) in chicken flocks. Similarly to other live MD vaccine viruses it is propagated in freshly prepared chicken embryo fibroblasts (CEF). In this study, MDV-1 CVI988/Rispens strain was adapted to QT35 cells.

Glycoprotein gD of MDV lacks functions typical for alpha-herpesvirus gD homologues.

Glycoprotein D (gD) belongs to family of conserved structural proteins of alpha-herpesviruses. During productive infection of cells by herpes simplex virus 1 (HSV-1) gD has several important functions, is involved in virus penetration to and release from infected cells and is one of main targets of neutralizing antibodies. Similar functions are shared also by other alpha-herpesvirus gD homologues.