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.

Cytomegalovirus infection in infancy: virological and immunological studies.

Immunological and virological studies on 18 infants with cytomegalovirus (CMV) infection were performed. Eleven of these infants were studied on multiple occasions over a period of 1 year. The patients were divided into three clinical groups based on the probable time of infection and the resulting variation in clinical presentation. General parameters of cell-mediated immunity as determined by E-rosette formation and lymphocyte proliferative responses to mitogens and antigens were found to be normal. Quantitation of CMV excretion in urine, CMV-specific immunofluorescent (IF) and complement-fixing (CF) antibody titres and CMV-specific cell-mediated immune responses were done on all patients at approximately monthly intervals. Throughout the study period all patients continued to excrete CMV despite the presence of high antibody titres to the virus. CMV-specific lymphocyte proliferative responses were absent or diminished in 15 of the 18 patients. The immunological and virological status of all patients was similar regardless of the clinical manifestation of infection.

A longitudinal analysis of lymphocyte proliferative responses to mitogens and antigens during human pregnancy.

T-cell number and mitogen- and antigen-induced lymphocyte proliferative were assessed longitudinally in 18 normal human pregnancies to examine the effects of pregnancy on cellular immunity. The T-cell percentage and mitogen-induced responses did not change significantly in pregnant women as compared to nonpregnant, non-postpartum control adults. However, cell-mediated immune responses to three antigens were dramatically depressed during the third trimester and then returned to early pregnancy levels by 90 days post partum. This reduction in antigen-specific cellular immunity may be necessary to prevent rejection of the histoincompatible fetus by the mother and at the same time may render women in late gestation more susceptible to infection.

Cytomegalovirus-specific humoral and cellular immune responses in human pregnancy.

Cytomegalovirus (CMV)-specific humoral and cellular immunity was evaluated prospectively during and after 19 normal human pregnancies. Seropositive pregnant subjects had lymphocyte proliferative responses to purified CMV antigen that were markedly depressed by the end of the third trimester of pregnancy despite persistent levels of complement-fixing and immunofluorescent antibodies to CMV. These reduced lymphocyte proliferative responses returned to levels detected early in pregnancy by one year after delivery. None of the subjects excreted CMV during the study period. General parameters of cellular immunity, including thymus derived-cell counts as determined by formation of erythrocyte rosettes and mitogen-induced lymphocyte proliferation, were unaffected. Reactivation of latent CMV during pregnancy might be related to transient depression of CMV-specific cellular immunity.