Cosmological Constraints from Multiple Probes in the Dark Energy Survey.

The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically confirmed type Ia supernova light curves, the baryon acoustic oscillation feature, weak gravitational lensing, and galaxy clustering. Here we present combined results from these probes, deriving constraints on the equation of state, w, of dark energy and its energy density in the Universe. Independently of other experiments, such as those that measure the cosmic microwave background, the probes from this single photometric survey rule out a Universe with no dark energy, finding w=-0.80_{-0.11}^{+0.09}. The geometry is shown to be consistent with a spatially flat Universe, and we obtain a constraint on the baryon density of Ω_{b}=0.069_{-0.012}^{+0.009} that is independent of early Universe measurements. These results demonstrate the potential power of large multiprobe photometric surveys and pave the way for order of magnitude advances in our constraints on properties of dark energy and cosmology over the next decade.

Surface expression of squamous cell carcinoma antigen (SCCA) can be increased by the preS1(21-47) sequence of hepatitis B virus.

A variant of the serpin squamous cell carcinoma antigen (SCCA) has been identified as a hepatitis B virus binding protein and high expression of SCCA has recently been found in hepatocarcinoma. Since HBV is involved in liver carcinogenesis, experiments were carried out to examine the effect of HBV preS1 envelope protein on SCCA expression. Surface and intracellular staining for SCCA was assessed by FACS analysis. Preincubation of HepG2 cells and primary human hepatocytes with preS1 protein or with preS1(21-47) tetrameric peptide significantly increased the surface expression of SCCA, without modification of its overall cellular burden, suggesting a surface redistribution of the serpin. An increase in HBV binding and internalization was observed after pre-incubation of the cells with preS1 preparations, compared to cells preincubated with medium alone. Pretreatment of cells with DMSO, while not influencing SCCA basal expression, was responsible for an increase in the efficiency of HBV internalization and this effect was additive to that obtained after incubation with preS1 preparations. In conclusion, the HBV preS1(21-47) sequence is able to induce overexpression of SCCA at the cell surface facilitating virus internalization, while the increased efficiency of HBV entry following DMSO addition is not mediated by SCCA.

Antiapoptotic effects of IL-15 on pulmonary Tc1 cells of patients with human immunodeficiency virus infection.

In the early phases of human immunodeficiency virus (HIV) disease a T-cell alveolitis sustained by cytotoxic T lymphocytes (CTL) with anti-HIV activity occurs in the lung. With the progression of HIV disease, pulmonary CTL become infected and their cytotoxic activity declines. To investigate the potential causes leading to this phenomenon, we evaluated T cells obtained from the bronchoalveolar lavage (BAL) of 18 HIV-infected patients with T-cell alveolitis. BAL T cells were CD45R0+/CD8+ defined as Tc1 cells because they expressed cytoplasmic interferon gamma (IFN-gamma) and were CXCR3+/IL-12Rbeta2+. Furthermore, they bore the interleukin (IL)- 15 receptor, Fas antigen, and tumor necrosis factor receptor (TNFR) type II. When cultured for 24 h highly purified BAL T cells showed an excessive spontaneous apoptosis; after activation with anti-CD3 or ionomycin, the proportion of T cells undergoing cell death increased. Interestingly, we found a direct relationship between the predisposition to undergo spontaneous apoptosis and the levels of Fas expression by BAL T cells. Alveolar macrophages (AMs) expressed high levels of IL-15 which paralleled the intensity of T-cell infiltration in most patients. The predisposition of CD8 T cells to undergo cell death was downregulated by the incubation with IL-15; the protective effect of the cytokine was dose-dependent. Nonetheless, AMs also expressed proapoptotic molecules, including membrane TNF-alpha (mTNF-alpha). Based on these observations it may be suggested that an excessive, spontaneous, and activation-induced apoptosis of pulmonary lymphocytes may be observed in HIV lung and that AMs are major regulators of T-cell homeostasis.

CXC chemokines IP-10 and mig expression and direct migration of pulmonary CD8+/CXCR3+ T cells in the lungs of patients with HIV infection and T-cell alveolitis.

The recruitment of cytotoxic T lymphocytes (CTL) is considered to be the major tool for the clearance of HIV from the lower respiratory tract. In this study we evaluated the pathophysiologic role of two lymphotactic CXC chemokines (IP-10 and Mig) in the lung of HIV-infected patients. These chemokines stimulate the directional migration of activated T cells and interact with a specific receptor (CXC receptor 3, CXCR3). Lymphocytes recovered from the bronchoalveolar lavage (BAL) of HIV-infected patients with high intensity T-cell alveolitis were CD8+ T cells expressing high levels of CXCR3 and IFN-gamma, a phenotype that is characteristic of Tc1 cells. Pulmonary T cells expressing CXCR3 exhibited a high migratory capability in response to IP-10 and Mig. Alveolar macrophages recovered from patients with T-cell alveolitis bore the IFN-gamma-inducible proteins IP-10 and Mig. A positive correlation was demonstrated between IP-10, Mig, and IL-15 expression by alveolar macrophages. Interestingly, macrophages isolated from the lung of HIV-infected patients with T-cell alveolitis secreted definite levels of CXCR3 ligands capable of inducing T-cell chemotaxis. Taken together, our data suggest that chemotactic ligands that bind CXCR3 contribute significantly to the accumulation of HIV-specific CTL in the lung.