CMV Towne Vaccine(Vical)

Objectives of this trial are to:
Evaluate the kinetics and magnitude of the CMV-specific immune response post-Towne challenge (3000 pfu) in healthy CMV-seronegative volunteers who received VCL CT02 administered ID or IM 9 to 15 months previously as measured by: 1) ELISA and/or virus-neutralizing antibody titers for gB; 2) T-cell IFN-g ELISPOT; 3) T-cell proliferation assays (CFSE) for IE1, pp65, and/or gB; and possibly 4) cytokine and phenotypic flow cytometry responses to pp65, IE1, and/or gB.
Evaluate the safety safety of Towne challenge in healthy CMV-seronegative adult subjects who have previously been immunized with a trivalent pDNA CMV vaccine (VCL-CT02) administered intramuscularly (IM) or intradermally (ID).
Our hypothesis is that the immune response to Towne vaccine 3000 pfu challenge after VLC-CT02 priming will be greater than that after Towne vaccination alone (concurrent controls will be administered Towne alone in a concurrent, companion trial).