In order to generate recombinant adenoviruses with the MPER insertions within the hexon regions, fragments of DNA corresponding to MPER, were generated by PCR from templates provided by Integrated DNA technologies. In our manuscript, the MPER sequence corresponds to EKNEKELLELDK-WASLWNWFDITN from HIV gp41. This fragment was subcloned into the BamHI site in the previously described HVR2-His 6 /pH5S plasmids [19] . To create Ad5 vectors containing HIV epitopes in the HVRs of hexon, these resulting plasmids were digested with EcoRI and PmeI. These resulting fragments containing the homologous recombination regions and the hexon genes were purified, then recombined with a SwaI-digested Ad5 backbone vector that lacks the hexon gene, pAd5/DH5 [26] . These recombination reactions were performed in Escherichia coli BJ5183 (Stratagene, La Jolla, CA). The resultant clone was designated as Ad5/HVR2-MPER-L15; in addition, there was another virus construct with this hexon modification, which contained the HIV Gag gene in the DE1 region: Ad5/HVR2-MPER-L15 (Gag). To create Ad5 vectors containing HIV Gag, the cytomegalovirus (CMV)-Gag construct was subcloned into an Ad DE1 shuttle plasmid. The resulting plasmid was digested with PmeI restriction enzyme. The resulting fragment containing the homologous recombination region at the Ad5 DE1 region was then recombined with the E1 deleted Ad5 backbone. AdCMVEnv was made as previously described [27] , This vector expresses the HIV 89.6 envelope (Env) gene under the control of the CMV promoter.