RECOMBINANT MAREK'S DISEASE VIRUS, PROCESS FOR PREPARING THE SAME AND VACCINE CONTAINING THE SAME

摘要

A recombinant Marek's disease virus produced by the mutation of a Marek's disease virus with a plasmid wherein said plasmid comprises (1) a gene fragment derived from the Us region or inverted repeat sequences adjacent to both ends of said Us region of a Marek's disease virus genome and (2) an exogenous gene expression cassette incorporated in said gene fragment, said cassette comprising an exogenous gene bound downstream of a promoter derived from an animal cell or an animal virus, a process for preparing the same, a multivalent live vaccine for birds comprising the same, and a vector for administration of a physiologically active substance to birds which comprises the same.