Changes in peripheral CD4⁺ T cell populations after IV SIVmac239 challenge.

<p>(A) Number of CD4⁺ T cells, and (B) the percentage of CD4⁺ CD95⁺ T cells in blood. (λ) Naïve control macaques (n = 7), (○) SHIV-immunized macaques (n = 5) and (5) Depo-Provera® SHIV-immunized macaques (n = 6). The number of CD4⁺ T cells (p = 0.0007) and the percentages of CD4⁺ CD95⁺ T cell (p<0.0001) were significantly higher (Friedman test) in the Depo-Provera®-treated, SHIV-immunized macaques than in the naïve control group.</p

Phthalhydrazide Chemiluminescence Method for Determination of Hydroxyl Radical Production: Modifications and Adaptations for Use in Natural Systems

The hydroxyl radical is formed through a variety of processes pertinent to natural and anthropogenic systems. Here we report development of a simple and sensitive trap-and-trigger chemiluminescence method based upon the hydroxylation of phthalhydrazide to 5-hydroxy-2,3-dihydro-1,4-phthalazinedione, which emits chemiluminescence when oxidized under alkaline conditions. Cu(III) is employed as an oxidant and is shown to be relatively insensitive to a range of interferences likely to be encountered. The method has been standardized by use of γ-radiolysis of water as a primary source of hydroxyl radical, with a convenient secondary calibration procedure developed that uses Fenton chemistry. Detection limits varied from 7.4 nM (at pH 3) and 6.2 nM (at pH 8.1) of accumulated hydroxyl radical production in a simple 10 mM NaCl matrix to around 30 nM in an artificial seawater medium, due to competition for hydroxyl between the phthalhydrazide probe and bromide. The method has been used to characterize the kinetics of the Fenton system employed for calibration and is shown to be consistent with published models of this process over time scales of several hours. The application of this method to a range of matrices and for photochemical studies is also described

pH Dependence of Hydroxyl Radical, Ferryl, and/or Ferric Peroxo Species Generation in the Heterogeneous Fenton Process

The heterogeneous Fenton process in the presence of Fe-containing minerals is ubiquitous in nature and widely deployed in wastewater treatment. While there have been extensive relevant studies, the dependence on pH of the nature and extent of oxidant generation and key reaction pathways remain unclear. Herein, the adsorption and decomposition of formate and H2O2 were quantified in the presence of ferrihydrite within the pH range of 3.0–6.0, and experiments with methyl phenyl sulfoxide were conducted to distinguish between HO• and weaker oxidant(s) which react via oxygen atom transfer including ferryl ion ([FeIVO]2+) and/or ferric hydroperoxo intermediates (FeIII(O2H)). Both HO• and [FeIVO]2+/FeIII(O2H) are concurrently produced on the surface over the acidic to near-neutral pH range. Despite the simultaneous formation of both oxidants, HO• is the major oxidant responsible for substrate oxidation in the interfacial boundary layer with [FeIVO]2+/FeIII(O2H) exhibiting limited exposure to substrates. With an increase of pH, the yield of both oxidants is inhibited by the decreasing availability of surface sites due to ferrihydrite particle aggregation. Increasing pH also favors the nonradical decay of H2O2 as evident from the consistent oxidant production rate relative to the surface area (SSA) despite an accelerated H2O2 decay rate relative to SSA with pH increase

Frequencies of regulatory CD4⁺ T cells after progesterone treatment and IV SIVmac239 challenge.

<p>A) Percentages of CD4⁺ CD152⁺ T cells in PBMC. B) Percent of CD4⁺ FoxP3⁺ HLA-DR⁺ T cells after challenge in PBMC. C) Percentages of CD4⁺ CD152⁺ T cells in axillary LN of the vaccinated animals at 12 weeks post-challenge. D) Percentages of CD4⁺ FoxP3⁺ HLA-DR⁺ T cells in axillary LN of the vaccinated animals at 12 weeks post-challenge. (λ) Naïve control macaques (n = 7), (○) SHIV-immunized macaques (n = 5) and (5) Depo-Provera®-treated, SHIV-immunized macaques (n = 6).</p

A Non-parametric Analysis of the CMB Power Spectrum

We examine Cosmic Microwave Background (CMB) temperature power spectra from the BOOMERANG, MAXIMA, and DASI experiments. We non-parametrically estimate the true power spectrum with no model assumptions. This is a significant departure from previous research which used either cosmological models or some other parameterized form (e.g. parabolic fits). Our non-parametric estimate is practically indistinguishable from the best fit cosmological model, thus lending independent support to the underlying physics that governs these models. We also generate a confidence set for the non-parametric fit and extract confidence intervals for the numbers, locations, and heights of peaks and the successive peak-to-peak height ratios.</p

Plasma vRNA levels after IV challenge with SIVmac239.

<p>(A) unimmunized macaques, (B) SHIV-immunized macaques and (C) progesterone-treated, SHIV-immunized macaques. In panel (D), cumulative vRNA levels over the 20 weeks of observation were transformed into areas under the curve (AUC) and the median AUC of the 3 groups of animals were compared. The Kruskal-Wallis test and a pair-wise comparison between the 2 groups of immunized animals and the unimmunized group using Dunn's multiple comparisons test were performed.</p

Cytokine mRNA levels after IV SIVmac239 challenge.

<p>Changes in gene expression are shown as the fold-change relative to the levels on the day of challenge for (A) TNF-α and (B) TGF-β. (C) Spearman rank correlation of TGF-β at 4 weeks PC, for all animals, with plasma viral RNA AUC between 1 and 20 weeks PC. (λ) Naïve control macaques (n = 7), (○) SHIV-immunized macaques (n = 5) and (5) Depo-Provera®-treated, SHIV-immunized macaques (n = 6).</p

Frequencies of activated T cells after progesterone treatment and IV SIVmac239 challenge.

<p>A) Percent of CD3⁺ CD4⁺ T cells expressing CD38 but not HLA-DR in PBMC. B) Percent of CD3⁺ CD8⁺ T cells expressing CD38 but not HLA-DR in PBMC. D) Percent of CD3⁺ CD8⁺ T cells expressing Ki-67⁺ in PBMC. E) Percent of CD3⁺ CD8⁺ T cells expressing caspase-3⁺ in PBMC. (○) SHIV-immunized macaques (n = 5) and (5) Depo-Provera®-treated, SHIV-immunized (n = 6).</p

SIV-specific T cell responses after IV SIVmac239 challenge.

<p>(A) Mean number of SIV Gag p27 interferon (IFN)-γ secreting cells in PBMC before and after challenge. (B) Median area under the curve for the total IFN-γ secreting cells in each group from week 2 to 16 PC, the time-points for which samples were available. (C) Mean SIV-specific T cell proliferative responses in PBMC expressed as the stimulation index (SI) before and after SIV challenge. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009814#s2" target="_blank"><i>Methods</i></a> for details. (D) Median area under the curve for the cumulative SI in each group from week -4 to 20 PC. (λ) Naïve control macaques (n = 7), (○) SHIV-immunized macaques (n = 5) and (5) Depo-Provera® SHIV-immunized macaques (n = 6). P values of a T test are indicated.</p

Frequency and functional capacity of Gag CM9- and GY9-specific CD8⁺ T cells of SHIV-immunized animals after IV SIVmac239 challenge.

<p>SIV-specific CD8⁺ T cell responses in cryopreserved PBMC from a <i>Mamu</i>-A*01 positive animal and a <i>Mamu</i>-A*02 positive animal in each vaccinated group are shown as pie charts. The number of positive SIV-specific T cells normalized to 10⁵ CD3⁺ T cells is shown for each response as the white number in the center of the pie chart. Each portion of a pie chart indicates the percentage of SIV-specific T cells that responded with one, two, or three functions; and the colored arcs around the pie show the cytokine or combination of cytokines comprising each response. ND not done, as samples were not available.</p