Mitochondrial DNA (mtDNA) of peripheral blood mononuclear cells (PBMCs) collected from Human immunodeficiency virus 1 (HIV-1)-infected patients and healthy controls were measured longitudinally using real-time polymerase chain reaction to evaluate the effects of antiretroviral agents on mtDNA synthesis in vivo and to assess the value of monitoring mtDNA in PBMCs to predict adverse events amongst these patients. MtDNA levels in PBMCs were significantly decreased in treatment-naive HIV-1-infected patients compared with healthy people. MtDNA levels were not only significantly correlated with CD4(+) T-cell count, but also inversely correlated with HIV-1 viral load. MtDNA levels in untreated patients and healthy controls were stable during the period of observation. On the other hand, amongst patients treated with regimens containing AZT/3TC or d4T/3TC, mtDNA increased during treatment and recovered to levels comparable to healthy controls. In contrast, mtDNA decreased immediately after the initiation of an AZT/ddC-containing regimen. We did not find a correlation between mtDNA levels and changes in clinical parameters. There was no significant difference in mtDNA levels between patients with and those without lipoatrophy. Furthermore, there was no obvious difference in mtDNA levels amongst those patients exhibiting signs and symptoms of peripheral neuropathy. In conclusion, the decrease in mtDNA levels in PBMCs amongst HIV-1-infected patients and its amelioration by antiretroviral therapy may suggest the influence of direct effects on mitochondria or mtDNA by HIV-1 infection. Further investigations are needed to elucidate the mechanisms contributing to decreased mtDNA and the value of mtDNA measurement in the care of HIV-1-infected individuals.

Although Japan is classified as a country with a low prevalence of human immunodeficiency virus type 1 (HIV-1), domestic sexual transmission has been increasing steadily. Because 70% of the Japanese population expresses HLA-A24 (genotype HLA-A*2402), we wished to assess the effect of the dominant HLA type on the evolution and transmission of HIV-1 among the Japanese population. Twenty-three out of 25 A24-positive Japanese patients had a Y-to-F substitution at the second position [Nef138-10(2F)] in an immunodominant A24-restricted CTL epitope in their HIV-1 nef gene (Nef138-10). None of 12 A24-negative Japanese hemophiliacs but 9 out of 16 patients infected through unprotected sexual intercourse had Nef138-10(2F) (P < 0.01). Two of two A24-positive but none of six A24-negative Australians had Nef138-10(2F). Nef138-10(2F) peptides bound well to the HLA-A*2402 heavy chain; however, Nef138-10(2F) was expressed poorly on the cell surface from the native protein. Thus, HIV-1 with Nef138-10(2F) appears to be a cytotoxic-T-lymphocyte escape mutant and has been transmitted frequently by sexual contact among the highly A24-positive Japanese population

Immune response enhanced by therapeutic HIV-1 vaccine may control viral proliferation after discontinuation of highly active antiretroviral therapy (HAART). Although which strategies for therapeutic vaccination are feasible remains controversial, application of dendritic cells (DCs) as a vaccine adjuvant represents a promising approach to improving deteriorated immune function in HIV-1-infected individuals. The safety and efficacy of DC-based vaccine loaded with HIV-1-derived cytotoxic T lymphocytes (CTL) peptides were thus investigated in this study. Autologous DCs loaded with seven CTL peptides with HLA-A*2402 restriction were immunized to four HIV-1-infected individuals under HAART. In terms of safety, peptide-loaded DCs were well tolerated, and only mild local and general symptoms were observed during vaccine administration. ELISPOT assays to detect IFN-gamma production in CD8(+) lymphocytes revealed a limited breadth of responses to immunized peptides in two of four participants, but no response in the remaining two participants. Differences in immunological response might be attributable to the fact that responders displayed higher nadir CD4 counts before starting HAART and were immunized with a larger number of DCs per reactive peptide than non-responders. Discontinuation of HAART after vaccination failed to lower viral set points compared to those before starting HAART. This early outcome warrants further exploration to elucidate the therapeutic value of vaccination with DCs in HIV-1 infection.

To evaluate the immunogenicity of human immunodeficiency virus (HIV) type 1 p55gag virus-like particles (VLPs) released by budding from yeast spheroplasts, we have analyzed the effects of yeast VLPs on monocytederived dendritic cells (DCs). Yeast VLPs were efficiently incorporated into DCs via both macropinocytosis and endocytosis mediated by mannose-recognizing receptors, but not the mannose receptor. The uptake of yeast VLPs induced DC maturation and enhanced cytokine production, notably, interleukin-12 p70. We showed that yeast membrane components may contribute to DC maturation partly through Toll-like receptor 2 signaling. Thus, Gag particles encapsulated by yeast membrane may have an advantage in stimulating Gag-specific immune responses. We found that yeast VLPs, but not the control yeast membrane fraction, were able to activate both CD4 ؉ and CD8 ؉ T cells of HIV-infected individuals. We tested the effect of cross-presentation of VLP by DCs in two subjects recruited into a long-term nonprogressor-slow progressor cohort. When yeast VLP-loaded DCs of these patients were cocultured with peripheral blood mononuclear cells for 7 days, approximately one-third of the Gag-specific CD8؉ T cells were activated and became perforin positive. However, some of the Gag-specific CD8 ؉ T cells appeared to be lost during in vitro culture, especially in a patient with a high virus load. Our results suggest that DCs loaded with yeast VLPs can activate Gag-specific memory CD8؉ T cells to become effector cells in chronically HIV-infected individuals, but there still remain unresponsive Gag-specific T-cell populations in these patients.