Thymidine kinase activity in cerebrospinal fluid of rabbits with Herpesvirus hominis encephalitis

The rabbit model of Herpesvirus hominis (HVH) encephalitis was utilized to determine whether thymidine (TdR) kinase (EC. 2.7.1.2.1), AN EARLY ENZYME IN THe HVH replicative cycle, is present in the cerebrospinal fluid (CSF) of rabbits with HVH encephalitis. The mean TdR kinase activity in CSF from infected rabbits was 2.30 plus or minus 1.69 pmol product/120 min/100 mul CSF, while the mean TdR kinase activity of uninfected CSF was 0.34 plus or minus 0.25. The enzyme appeared to be cell associated since the TdR kinase activity in the sedimented cell suspension was 5.08 plus or minus 2.93 (seven values) while the supernatant activity was 0.14 plus or minus 0.31 (seven values). To allow a comparison of TdR kinase from infected rabbit CSF with HVH and rabbit mononuclear cell TdR kinase, the mean ratio of TdR kinase activity at pH 6.0/pH 8.0, for infected rabbit CSF is intermediate between the ratio for HVH TdR kinase (P less than 0.001) and rabbit mononuclear cell TdR kinase (P less than 0.05).