Cytomegalovirus vaccine. Specific humoral and cellular immune responses in human volunteers.

Four seronegative adult male volunteers were immunized with Towne strain cytomegalovirus (CMV) vaccine. The only reaction was transient pain and swelling at the inoculation site. Viral cultures were performed during the first 12 weeks after immunization, and CMV was not recovered from throat, urine, or peripheral blood mononuclear cells. Both CMV-specific humoral and cellular immunity developed within three weeks of vaccination. Whereas humoral antibody titers declined steadily with time, the cellular immune responses seemed biphasic. An early peak in lymphocyte proliferation to CMV antigen occurred three to six weeks after immunization. Responses then diminished but increased again six to ten months after immunization. This study in a small group of normal male volunteers indicated that CMV vaccine was safe and immunogenic. That CMV vaccine elicited CMV-specific humoral and cell-mediated immunity is important, because there is evidence that both are necessary for protection from CMV infections.