The fact that we found increased neutralizing antibody titers but not increased FV-specific CD4+ T cell responses makes this approach all the more appealing for HIV vaccine development, as HIV preferably infects HIV-specific CD4+ T cells [37] and vaccine-induced HIV-specific CD4+ T cells have come under close scrutiny for a potential role in augmented infection rates in non-human primate and human vaccinees in several preclinical and clinical studies [38–40]. Here, CD4 is linked to infection.