Site-directed mutation in a conserved kinase domain of human cytomegalovirus-pp65 with preservation of cytotoxic T lymphocyte targeting

The major target of human cytomegalovirus (CMV)-specific cytotoxic T lympho cytes (CTL) is the tegument protein CMVpp65. However, this protein has prot ein kinase (PK) activity, and the unknown effects on cell replication of an exogenous PK in healthy cells could limit the use of CMVpp65 as a vaccine, especially in children. In this report we show that a point mutation conve rting lysine to asparagine at the invariant lysine (K436), an essential sit e for phosphotransfer, abolishes the threonine kinase activity. The mutant CMVpp65 maintains its immunologic target characteristics, including antibod y and CTL reactivity. This kinase-deficient CMVpp65 is a candidate for eval uation in future CMV vaccine development. (C) 2001 Published by Elsevier Sc ience Ltd.