During the course of infection with HIV-1, striking alterations in the subset distribution of peripheral blood gammadelta T cells are observed. While TCR Vdelta2 expression dominates among peripheral blood gammadelta T cells in healthy adults, there is a clear preponderance of Vdelta1 cells in HIV-1-infected persons. In this study, we present the first flow cytometry (FCM) analysis of the complete TCR Vgamma gene repertoire in HIV-1-infected individuals using a panel of mAb against all expressed Vgamma genes. The quantitative analysis of TCR Vgamma transcripts after amplification of cDNA by inverse PCR suggested that Vgamma5 usage is increased in HIV-1+ donors. This was confirmed by FCM with a new anti-Vgamma5 mAb. In addition, all members of the TCR VgammaI gene family (i.e. Vgamma2, 3, 4, 5 and 8) were expressed on significantly higher percentages of gammadelta T cells in HIV+ as compared to HIV- donors, whereas VgammaII (Vgamma9) expression was drastically reduced. No preferential association of the expanded Vdelta1+ cells with a particular Vgamma gene was observed in HIV-1 + donors. These results indicate that the increase in Vgamma1+ cells during HIV-1 infection occurs independently of the Vgamma gene usage and support the hypothesis that a Vdelta1-selective ligand might be involved.