ITIH4 and HIV infectious disease: In our previously reported Phase I clinical trial (DP6-001) of a polyvalent gp120 DNA prime-protein boost HIV vaccine (PDPHV), healthy adult volunteers who were negative for HIV infection first received three immunizations of a DNA plasmid mixture, including five expressing gp120 antigens from diverse HIV-1 subtypes, followed by two protein immunizations of five recombinant gp120 proteins matching those in the DNA prime immunization (Fig. 1a).