Shuzo Matsushita

Elevated Plasma Stromal Cell-Derived Factor 1 Protein Level in the Progression of HIV Type 1 Infection/AIDS

Stromal cell-derived factor 1 (SDF-1) is a unique chemokine involved in multiple organogenesis as well as in the regulation of HIV infection. Here we determined the plasma SDF-1 concentrations of 193 HIV-1-infected individuals and 154 normal Japanese volunteers by developing a highly sensitive measurement system based on time-resolved fluoroimmunoassay (SDF-1 TR-FIA). This system is also valid for the mouse model to quantitate circulating SDF-1 concentration in vivo and thereby its correlation with CXCR4 expression level on CD4(+) T cells. Interestingly, plasma SDF-1 concentrations in HIV-1-infected individuals were three times higher than those in a normal control group and plasma SDF-1 protein levels showed an inverse correlation with CD4(+) T cell count and a positive correlation with plasma HIV-1 RNA load. Notably, individuals with later stage HIV-1 infection, who maintained fewer than 200 CD4(+) T cells per cubic milliliter and more than 10,000 copies of HIV-1 RNA per milliliter, showed the highest plasma SDF-1 level among individuals at any stage of HIV-1 infection. These results suggest that endogenous SDF-1 is upregulated by HIV-1 infection, particularly in late-stage HIV-1 infection/AIDS.

Susceptibility of Mink (Mustera vision)-Derived Cells to Replication by Human Immunodeficiency Virus Type 1

ABSTRACT In vivo studies for understanding viral transmission and replication, host immune responses, and pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection would greatly benefit from the establishment of a small-animal model. In this study, we explored the potential of American mink (Mustera vison) as a susceptible host. We found that primary cells and cell lines derived from this species efficiently supported trans-activation of the HIV-1 long terminal repeat by Tat. Accordingly, the cysteine residue at position 261, which has been shown to be important for interaction of the human cyclin T1 with the HIV-1 regulatory protein Tat, is conserved in the mink homologue. No species-specific defect in Rev function could be detected in mink cells. In addition, primary splenocytes, fibroblasts, and the Mv.1.Lu cell line from American mink supported early as well as late HIV-1 gene expression following infection with vesicular stomatitis G protein-pseudotyped HIV-1 viruses, at levels comparable to those seen with permissive human cells. Furthermore, the mink Mv.1.Lu cell line stably expressing human CD4 and CCR5 receptors supported a spreading HIV-1 infection with few, if any, deficiencies compared to findings in human cell lines. This indicates the potential of HIV-1 to replicate in these cells once the blockade at the stage of virus entry has been removed. These results clearly show that cells from American mink generally pose no functional intracellular block to HIV-1 replication, and collectively they raise the possibility that this animal species could be engineered to support HIV-1 infection, providing a useful small-animal model for evaluating de novo infection by HIV-1.

Advance in Treatment Strategy and Immune Reconstruction against HIV‐1 Infection

HIV‐1 can be considered an infection of the immune system, resulting in progressive and ultimately profound immune suppression. The availability of highly active antiretroviral therapy (HAART) has resulted in dramatic changes in the disease course in persons fortunate enough to have access to these medications, but long‐term therapy is limited by the development of resistance as well as toxicities of the potent medication regimens. Emerging data indicate that individuals who have non‐progressive clinical course control HIV‐1 immunologically. This has bolstered hope that the immune response might be effectively augmented in persons with HIV infection. Recent data indicating that immediate treatment of acute infection leads to augmentation of antiviral immune responses have provided evidence that the immune system might be enhanced in certain situations. Therefore, investigation in the reconstitution of anti‐HIV immune response in patients under HAART should provide encouragement for continuing to explore methods to obtain meaningful and durable immune enhancement as an adjunct to HAART in HIV‐1 infection.

The impact of highly active antiretroviral therapy by the oral route on the CD8 subset in monkeys infected chronically with SHIV89.6P

The objective of this study was to assess the impact of highly active antiretroviral therapy (HAART) by an oral route on the peripheral blood CD8 subset in the monkeys infected persistently with a pathogenic strain, SHIV(89.6P). Two rhesus macaques were inoculated intravenously with SHIV(89.6P), then treated with the combination of AZT, 3TC and Lopinavir/Ritonavir (LPV/RTV) as recommended in humans by the oral route with confectionery continued for 28 days. In one of two chronically infected macaques, MM260, the viral load was maintained in the range of 10(4)-10(5) copies/ml before HAART. The plasma viral load and proviral DNA decreased dramatically during the treatment, and cessation of this therapy the viral load rebounded to the pre-treatment level but the proviral DNA rebound was delayed. The other monkey, MM242, had low viral loads (1.2x10(3)-<5x10(2) copies/ml) both before and after HAART. CD4(+) and CD8(+) T cell counts and proviral DNA level were not significantly changed after the treatment. The percentages of CD8(+)CD45RA(-)Ki67(+)cells increased during (MM260) or after (MM242) HAART and the subset was maintained at a high percentage until 18 weeks post HAART in MM242. These findings suggest that this primate model might serve an important role in testing the virological and immunological efficacy of novel therapeutic strategies combined with HAART.