This is a hypothesis-generating descriptive study to evaluate the kinetics and pattern of early innate and adaptive immune responses to the VRC recombinant adenoviral vector serotype 5 vaccine, VRC-HIVADV014-00-VP (rAd5). The rAd5 vaccine has been previously administered to more than 1000 study subjects and characterized as safe and immunogenic. A difference in the pattern of vaccine antigen-specific immune responses observed when rAd5 is given as a single agent compared to after priming by a 6-plasmid DNA vaccine, VRCHIVDNA016-00-VP, has previously been reported. This study will randomize vaccine-naive subjects to receive a single injection of rAd5 or to the DNA primerAd5 boost regimen that is now in a large Phase II study. Collection of blood, rectal, oral and genital specimens for characterization of early innate and adaptive immune responses will follow receipt of rAd5. The hypothesis is that the pattern of early innate and adaptive immune responses elicited by the rAd5 vaccine administered after priming with DNA vaccine will be distinctly different from the pattern elicited when rAd5 is administered as a single agent. The primary objectives are to describe the kinetics and pattern of early innate and adaptive immune responses that occur in blood samples early after administration of rAd5 vaccine alone and after administration following 3 DNA prime injections. Secondary and exploratory objectives are related safety, as well as the pattern of immune responses in mucosal samples and in blood samples.