Further characterisation of a variant type of turkey herpesvirus which releases large quantities of cell‐free viruses into culture medium

Abstract

SUMMARYA variant type of turkey herpesvirus (HVT/VT) which releases large quantities of cell-free virus into its culture medium was compared with the prototype of the FC 126 strain of HVT (HVT/WT) as to the biological and serological characteristics. The lack of replication-defective HVT/VT in chickens was considered to be due to the inability of the virus to infect and replicate in lymphocytes and not to temperature-sensitive defects at 41°C. No obvious antigenic differences were found between HVT/VT and HVT/WT in agar gel precipitation and neutralisation tests using four specific antisera prepared in chickens hyperimmunised with cells infected with HVT/WT or HVT/VT and cultural supernatants of cells infected with HVT/WT or HVT/VT. Group-specific (gs) A and gs B antigens were released into the culture medium from cells infected with HVT/VT.