Haploinsufficiency identifies STAT5 as a modifier of IL-7-induced lymphomas.

The requirement for receptor components and the signalling effector, signal transducer and activator of transcription (STAT) 5A/5B, was assessed genetically in a lymphoma development model induced by interleukin-7 (IL-7). This growth factor for T- and B-cell progenitors and mature lymphocytes activates survival and proliferative pathways including Bcl-2, phosphatidylinositol-3 kinase and STAT5. Overexpression of IL-7 in vivo causes early mortality from lymphoma development.

Expression of the diffuse B-cell lymphoma family molecule SWAP-70 in human B-cell neoplasms: immunohistochemical study of 86 cases.

SWAP-70 is a recently discovered member of the Dbl (diffuse B-cell lymphoma) family of signal transduction molecules that is abundantly expressed in B cells. SWAP-70 mediates lipid second-messenger signals to the cytoskeletal-organizing GTPase Rac, functioning as a guanine-nucleotide exchange factor. SWAP-70 is strongly expressed in germinal center B cells, with low-level expression in resting B-cells.

Loss of tolerance and autoimmunity affecting multiple organs in STAT5A/5B-deficient mice.

STAT5 has previously been reported to be dispensable for the maintenance of tolerance in vivo. However, in examining hemopoiesis in mice lacking both isoforms of STAT5, STAT5A, and STAT5B, we noted that a subset of these mice demonstrated dramatic alterations in several bone marrow progenitor populations concomitant with lymphocytic infiltration of the bone marrow. In addition, cellular infiltration affecting the colon, liver, and kidney was observed in these mice.

HDAC7, a thymus-specific class II histone deacetylase, regulates Nur77 transcription and TCR-mediated apoptosis.

We report that HDAC7, a class II histone deacetylase, is highly expressed in CD4(+)CD8(+) double-positive thymocytes. HDAC7 inhibits the expression of Nur77, an orphan receptor involved in apoptosis and negative selection, via the transcription factor MEF2D. HDAC7 is exported from the nucleus during T cell receptor activation, leading to Nur77 expression.

Increased virus replication and virulence after serial passage of human immunodeficiency virus type 2 in baboons.

Similar to human immunodeficiency virus type 1 (HIV-1) infection of humans, the natural history of HIV-2 infection in baboons (Papio cynocephalus) is a slow and chronic disease that generally takes several years before an AIDS-like condition develops. To shorten the amount of time to the development of disease, we performed five serial passages of HIV-2(UC2) in baboons by using blood and bone marrow samples during the acute phase of infection when viral loads were at high levels. After these serial passages, virus levels in plasma, peripheral blood mononuclear cells (PBMC) and lymphatic tissues in the acutely infected baboons were increased.

HIV-related neuropathology, 1985 to 1999: rising prevalence of HIV encephalopathy in the era of highly active antiretroviral therapy.

Postmortem neuropathologic reports for a consecutive series of 436 HIV-seropositive patients who died between 1985 and 1999 were matched with clinical data for 371 of them. Cases were divided into four groups depending on the date of death. The chosen time periods reflected the type of antiretroviral therapy available: before 1987 (before zidovudine); 1987-1992, the period of monotherapy (nucleoside analog reverse transcriptase inhibitors [NRTIs]); 1993-1995, the era of the use of dual NRTI combinations; and 1996-1999, the era of highly active antiretroviral therapy (HAART) containing protease inhibitors.

Productive infection of plasmacytoid dendritic cells with human immunodeficiency virus type 1 is triggered by CD40 ligation.

Immature plasmacytoid dendritic cells are the principal alpha interferon-producing cells (IPC), responsible for primary antiviral immunity. IPC express surface molecules CD4, CCR5, and CXCR4, which are known coreceptors required for human immunodeficiency virus (HIV) infection. Here we show that IPC are susceptible to and replicate HIV type 1 (HIV-1).

Injection of human primary effusion lymphoma cells or associated macrophages into severe combined immunodeficient mice causes murine lymphomas.

The pathogenesis of immunodeficiency-associated lymphoma is poorly understood. During the past several years, numerous lines of evidence implicating a multistep process of malignant transformation, also known as sequential pathogenesis, have emerged. Tumor-associated macrophage production of specific lymphostimulatory products has been demonstrated and hypothesized to be central to this process.

Development of WF10, a novel macrophage-regulating agent.

WF10 represents a new class of drug involved in regulating macrophage function both in vitro and in vivo. In the US, WF10 is being evaluated in patients with advanced HIV infection as an adjunct to highly active antiretroviral therapy (HAART). To date, most therapeutic efforts to treat HIV infection have focused on inhibition of viral replication with the goal of decreasing viral load.

Increased HLA-DR expression on peripheral blood monocytes in subsets of subjects with primary HIV infection is associated with elevated CD4 T-cell apoptosis and CD4 T-cell depletion.

Whereas T-cell activation parameters of HIV disease have been extensively studied, the activation status of circulating monocytes has received less attention. Sixty-one subjects with primary HIV infection were evaluated by fluorescent-activated cell sorter (FACS) analysis at baseline (pretreatment) for CD4 T-cell count, CD4 T-cell apoptosis, and immune activation. A subset of 15 subjects with marked elevated (3 standard deviations above normal) monocyte DR expression had significantly reduced CD4 T-cell counts at baseline (p <.

Progress toward a human CD4/CCR5 transgenic rat model for de novo infection by human immunodeficiency virus type 1.

The development of a permissive small animal model for the study of human immunodeficiency virus type (HIV)-1 pathogenesis and the testing of antiviral strategies has been hampered by the inability of HIV-1 to infect primary rodent cells productively. In this study, we explored transgenic rats expressing the HIV-1 receptor complex as a susceptible host. Rats transgenic for human CD4 (hCD4) and the human chemokine receptor CCR5 (hCCR5) were generated that express the transgenes in CD4(+) T lymphocytes, macrophages, and microglia.