It is possible that the presence of detectable neutralizing antibody to a given DENV serotype 6 to 12 months after vaccination may be a more specific indicator of the induction of homologous protective immunity compared with that detected 1 month after vaccination, because maturation of the adaptive immune response preserves production of the highest affinity antibodies by long-lived plasma cells in the bone marrow. varicella computer virus or with a booster dose of Hib Pomalidomide-C2-amido-(C1-O-C5-O-C1)2-COOH during the second 12 months of life. Study cohorts. Sequential vaccinations of dose-escalating cohorts (cohorts A, B, and C) were planned with increasing numbers of subjects per cohort. To ensure the safety of subjects, an initial cohort of six infants was initially assigned to cohort A to receive either low-dose DENV vaccine or control vaccine. Fifteen and thirty infants were assigned, respectively, to cohorts B and C to receive either full-dose DENV vaccine or control vaccine. After administration of dose 1 for a given cohort, the 21-day post-dose 1 reactogenicity data were reviewed, preserving the blind, by the IDMC and the US Food and Drug Administration. Based on acceptable safety profiles, the IDMC permitted vaccinations of the following cohort. Cohort A received a low-dose (one-tenth of full dose) DENV vaccine candidate (= 4) or control vaccine (= 2). Cohort B received full-dose DENV vaccine (= 10) or control vaccine (= 5). Cohort C received full-dose DENV vaccine (= 20) or control vaccine (= 10). Vaccines. DENV vaccine candidate. The tetravalent DENV vaccine candidate was prepared before administration from rehydrated freeze-dried monovalent vaccines (Table 1) that were mixed in equal volumes in a sterile glass vial for delivery of up to six doses. The monovalent vaccines were produced for each DENV serotype at the Salk Institute, Swiftwater, PA.10 For the one-tenth dose, 1.0 mL full-dose preparation was diluted in 9.0 mL diluent of Eagle’s Minimum Essential Medium. Each DENV vaccine dose was administered as a 1.0-mL subcutaneous injection by an Pomalidomide-C2-amido-(C1-O-C5-O-C1)2-COOH unblinded vaccination team according to written procedures; these staff also administered the control vaccines and did not participate in the evaluation of subjects thereafter. Quality control staff and external observers monitored these processes. Freeze-dried monovalent DENV vaccines were transported on dry ice from WRAIR, Silver Planting season, MD to AFRIMS, Bangkok, Thailand, where they were stored at ?70C until reconstitution around the morning of vaccinations. All DENV vaccine preparations were held on ice through all dilution, reconstitution, and blending procedures to prepare the tetravalent vaccine. The monovalent vaccines were returned to ?70C storage immediately after blending to make the tetravalent vaccine. The tetravalent vaccines remained on ice until completion of Rabbit polyclonal to PIWIL2 vaccinations ( 8 hours from reconstitution); at that time, they were stored at ?70C. All infants assigned to a given cohort were scheduled for vaccination over a 1- or 2-day period. Vaccination required formulation of tetravalent vaccine from lyophilized monovalent vaccines on eight occasions, including two occasions when additional 10-fold dilutions were conducted. On each of the days that this DENV vaccine was formulated, retained samples of tetravalent product were frozen at ?70C, subsequently transported to WRAIR on dry ice, and returned to ?70C storage until thawed for potency testing using an immunofocus assay (IFA) as previously explained.12 Control vaccines. Varicella (type B (mosquitoes (a quantal response assay to determine 50% mosquito infectious doses per 1 mL [MID50/mL] of serum). Even though limit of detection (LOD) for the qRT-PCR is usually 5 RNA copies for DENV-1, -2, and -3 and 25 RNA copies for DENV-4, no LOD has been defined for the quantal response assay given its inherent biological variability.3 Data analysis. All statistical analyses were performed Pomalidomide-C2-amido-(C1-O-C5-O-C1)2-COOH using SAS software (version 8.2; SAS, Cary, NC). Security analyses were performed around the per-protocol cohort and stratified by treatment cohort (cohorts A, B, and C and control) with the full-dose DENV vaccine groups (cohorts B and C) pooled. The overall percentages of subjects reporting an AE after vaccine administration (21 days for solicited AEs after each DENV/control vaccination, 7 days for solicited AEs after JEV vaccination, and 30.