Optimization of DNA immunization against human cytomegalovirus

The immune responses of mice injected with plasmids VR-gB and VR-gB Delta t m expressing the full-length membrane-anchored, or secreted forms of human cytomegalovirus (HCMV)-glycoprotein B (gB), respectively, and VR-pp65 expre ssing the HCMV-phosphoprotein 65 (pp65) were analyzed. Pretreatment of mice with the local anesthetic bupivacaine did not enhance antibody production, and IFN-alpha co-expressed with the immunizing plasmids induced a moderate increase in the antibody response. However, antibody response was higher i n mice inoculated at three sites in the musculus quadriceps than in mice in oculated at one site with the same dose and in the same muscle. pVR-gB Delt a tm induced significantly higher antibody titers than the construct expres sing the membrane-anchored form of gB, and priming with pVR-gB Delta tm fol lowed by boosting with the gB subunit resulted in high-titer antibody respo nses. Immunization with VR-pp65 induced dose-dependent CTL responses in abo ut 50% of the mice at a dose of 50 mug. Go-expression of IFN-alpha did not affect the number of responding mice. These findings might be important for optimization of humoral and cellular immune responses to HCMV after DNA va ccination. (C) 2001 Elsevier Science Ltd. All rights reserved.