Increased soluble IL-7 receptor concentrations associate with improved IL-7 therapy outcomes in SIV-infected ART-treated Rhesus macaques

The use of interleukin-7 (IL-7) as an immunorestorative therapeutic has proven effective in HIV infection, cancer and bone marrow transplantation. Mediating its activity through membrane-bound IL-7 receptor α (mCD127), IL-7 therapy increases T-cell numbers and survival. A soluble form, sCD127, is found in plasma, and we have previously identified increased plasma sCD127 concentrations in HIV infection. Furthermore, patients with high sCD127 exhibited the best viral control, implicating a role for IL-7 or sCD127 directly in improved viro-logic/immunologic outcomes. The role of the cytokine IL-7 in elevating sCD127 levels was addressed here through assessment of retrospective samples obtained from SIV-infected antiretroviral (ART)-treated Rhesus macaques. IL-7 was administered in clustered weekly doses, allowing for an assessment prior, during and following IL-7 administration. The levels of sCD127 remained relatively unchanged during both early SIV infection and following initiation of ART. However, treatment with IL-7 increased sCD127 concentrations in most animals, transiently or persistently, paralleling increased T-cell numbers, correlating significantly with CD8+ T-cell levels. In addition, proliferating CD4+ or CD8+ T-cells (measured by Ki67) increased in association with elevated sCD127 concentrations. Finally, a high concentration of sCD127 in IL7-treated animals was associated with increased retention of T-cells (measured by BrDU). In addition, a lack, or loss of viral control was associated with more pronounced and frequent elevations in plasma sCD127 concentrations with IL-7 therapy. In summary, plasma sCD127 levels in SIV-infected ART-treated macaques was associated with therapeutic IL-7 administration, with higher sCD127 levels in macaques demonstrating the best T-cell responses. Thi

Data from: Increased soluble IL-7 receptor concentrations associate with improved IL-7 therapy outcomes in SIV-infected ART-treated Rhesus macaques

The use of interleukin-7 (IL-7) as an immunorestorative therapeutic has proven effective in HIV infection, cancer and bone marrow transplantation. Mediating its activity through membrane-bound IL-7 receptor α (mCD127), IL-7 therapy increases T-cell numbers and survival. A soluble form, sCD127, is found in plasma, and we have previously identified increased plasma sCD127 concentrations in HIV infection. Furthermore, patients with high sCD127 exhibited the best viral control, implicating a role for IL-7 or sCD127 directly in improved virologic/immunologic outcomes. The role of the cytokine IL-7 in elevating sCD127 levels was addressed here through assessment of retrospective samples obtained from SIV-infected antiretroviral (ART)-treated Rhesus macaques. IL-7 was administered in clustered weekly doses, allowing for an assessment prior, during and following IL-7 administration. The levels of sCD127 remained relatively unchanged during both early SIV infection and following initiation of ART. However, treatment with IL-7 increased sCD127 concentrations in most animals, transiently or persistently, paralleling increased T-cell numbers, correlating significantly with CD8+ T-cell levels. In addition, proliferating CD4+ or CD8+ T-cells (measured by Ki67) increased in association with elevated sCD127 concentrations. Finally, a high concentration of sCD127 in IL7-treated animals was associated with increased retention of T-cells (measured by BrDU). In addition, a lack, or loss of viral control was associated with more pronounced and frequent elevations in plasma sCD127 concentrations with IL-7 therapy. In summary, plasma sCD127 levels in SIV-infected ART-treated macaques was associated with therapeutic IL-7 administration, with higher sCD127 levels in macaques demonstrating the best T-cell responses. This study furthers our knowledge regarding the interrelationship between increased IL-7 levels and elevated sCD127 levels that may have implications for future IL-7 immunotherapeutic approaches in HIV-infected patients

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Phylogenetic analysis of methanotrophic communities in cover soils of a landfill in Ontario

We examined the methanotrophs in the Trail Road Landfill soils, Ottawa, Ontario, through cultivation-independent molecular assay and the culturing approach. Denaturing gradient gel electrophoresis (DGGE) analysis of amplified methanotroph-specific 16S rDNA gene fragments revealed a more diverse type I (RuMP pathway) methanotrophic community than type II (serine pathway) in 17 soil samples taken along a 50 m transect. The type II methanotrophic community was less diverse, with the dominance of Methylocystis in almost all samples, and clustering with high similarity (85%\u201388%). Also, the results showed that the C/N ratio of soil organic matter could significantly affect the methanotrophic community structures. The DGGE results were supported by sequence analysis of cloned pmoA. Members of the genera Methylobacter (type I), Methylocaldum (type X), and Methylocystis (type II) appeared to be the dominant methanotrophs. From methanotrophic enrichments, we isolated type I Methylobacter sp., and 3 type II Methylocystis spp.,which appeared to be one of the dominant bacteria species in the soil sample from which isolates were obtained.Nous avons examin\ue9 les m\ue9thanotrophes retrouv\ue9s dans des sols provenant de la d\ue9charge Trail Road \ue0 Ottawa, Ontario, \ue0 l'aide de techniques mol\ue9culaires ne n\ue9cessitant pas la culture de micro-organismes, et aussi \ue0 l'aide de cultures. \ue9 m\ue9thanotrophe de type II \ue9tait moins diversifi\ue9e, et la dominance de Methylocystis a \ue9t\ue9 observ\ue9e dans presque tout les \ue9chantillons, et \ue9tait regroup\ue9e dans un amas avec une similarit\ue9 \ue9lev\ue9e (85 %-88 %). Aussi, les r\ue9sultats ont montr? que le ratio C/N de la mati\ue8re organique du sol pouvait affecter de mani\ue8re significative la structure de la communaut\ue9 m\ue9thanotrphe. Les r\ue9sultats obtenus \ue0 l'aide du DGGE sont support\ue9s par l'analyse de s\ue9quence pmoA clon\ue9es. Les membres des genres Methylobacter (type I), Methylocaldum (type X) et Methylocystis (type II) sont apparus comme \ue9tant les m\ue9thanotrophes dominants. \uc0 partir d'enrichissements m\ue9thanotrophes, nous avons isol\ue9 une souche de Methylobacter sp. de type I et 3 Methylocystis de type II qui semblait \ueatre une des esp\ue8ces bact\ue9riennes dominantes dans l'\ue9chantillon de sol \ue0 partir duquel des isolats ont \ue9t\ue9 obtenus.Peer reviewed: YesNRC publication: Ye

Generalized Liver- and Blood-Derived CD8⁺ T-Cell Impairment in Response to Cytokines in Chronic Hepatitis C Virus Infection

<div><p>Generalized CD8⁺ T-cell impairment in chronic hepatitis C virus (HCV) infection and the contribution of liver-infiltrating CD8⁺ T-cells to the immunopathogenesis of this infection remain poorly understood. It is hypothesized that this impairment is partially due to reduced CD8⁺ T-cell activity in response to cytokines such as IL-7, particularly within the liver. To investigate this, the phenotype and cytokine responsiveness of blood- and liver-derived CD8⁺ T-cells from healthy controls and individuals with HCV infection were compared. In blood, IL-7 receptor α (CD127) expression on bulk CD8⁺ T-cells in HCV infection was no different than controls yet was lower on central memory T-cells, and there were fewer naïve cells. IL-7-induced signalling through phosphorylated STAT5 was lower in HCV infection than in controls, and differed between CD8⁺ T-cell subsets. Production of Bcl-2 following IL-7 stimulation was also lower in HCV infection and inversely related to the degree of liver fibrosis. In liver-derived CD8⁺ T-cells, STAT5 activation could not be increased with cytokine stimulation and basal Bcl-2 levels of liver-derived CD8⁺ T-cells were lower than blood-derived counterparts in HCV infection. Therefore, generalized CD8⁺ T-cell impairment in HCV infection is characterized, in part, by impaired IL-7-mediated signalling and survival, independent of CD127 expression. This impairment is more pronounced in the liver and may be associated with an increased potential for apoptosis. This generalized CD8⁺ T-cell impairment represents an important immune dysfunction in chronic HCV infection that may alter patient health.</p></div

IL-7 therapy-mediated effects on T-cell survival is associated with increases in plasma sCD127 concentrations.

<p>T-cell survival graphs for all animals in the IL-7 treatment group. In all plots, an arbitrary, yet common crossing point of 5 BrDU⁺ cells/μl of blood is indicated by a dotted line. The clustered administration of IL-7 is indicated on the x-axis by groups of three arrows and the first day of the BrDU injections is also indicated.</p

Increased plasma sCD127 concentrations correlated with IL-7-induced increases in CD8⁺ T-cells in SIV-infected Rhesus macaques.

<p>(A-D) Representative graphs of IL-7-treated animals whose concentration of plasma sCD127 increased with changes in absolute CD8⁺ T-cell numbers in at least one IL-7 cluster during the cytokine treatment time period. (E) In the animal that maintained viral control, plasma sCD127 concentrations did not appear to associate with changes CD8⁺ T-cell numbers. Total number of IL-7-treated animals in which data of absolute T-cells was available: n = 5. The clustered administration of IL-7 is indicated on the x-axis by groups of three arrows.</p

Plasma sCD127 concentrations are unaffected by SIV infection or antiretroviral therapy in Rhesus macaques.

<p>The concentration of sCD127 in plasma samples of Rhesus macaques prior to SIV infection, after infection, following ART initiation (>105 d.p.i.) was determined using a CD127 microbead immunoassay. The minimum detection limit of the immunoassay is 5 ng/ml. (A) Plasma concentrations of sCD127 did not change following SIV infection or after ART (paired Student’s <i>t</i>-test, n = 4) in the control group. (B) The concentration of plasma sCD127 (mean, +/- SD) is shown relative to viral loads for each animal in the control group over time (0–380 d.p.i.). Plasma samples for RM23892 (day -7 until day 105 post-infection) could not be located for the quantification of sCD127 in this retrospective study.</p

Plasma sCD127 concentrations increased and persisted after IL-7 administration to ART-treated SIV-infected Rhesus macaques.

<p>The concentration of sCD127 in plasma samples of Rhesus macaques prior to SIV infection, after infection, following ART initiation (>105 d.p.i.) and after each administration of IL-7 (started at 142 d.p.i.) was quantified by a CD127 microbead immunoassay (min. detection limit: 5 ng/ml). (A) Plasma sCD127 concentrations transiently increased in all SIV-infected, ART-treated animals that were administered rsIL-7-gly (n = 5). In some cases, these increases persisted for 3–5 weeks. (B) The concentration of plasma sCD127 (mean, +/- SD) is shown relative to viral loads for each animal in the IL-7-treated group over time (0–380 d.p.i.). (C-G) Changes in sCD127 concentrations also varied by IL-7 cluster, depending on the individual. In the first cluster of IL-7 administration, 3 of 5 animals (C, D and E) demonstrated a sharp increase in plasma sCD127 concentrations before the next cluster. The second cluster of IL-7 treatment increased sCD127 release in 2 animals (E and G). Plasma sCD127 concentrations increased in the third cluster in 3 of 5 animals (D, E and G). Transient increases in plasma sCD127 concentrations persisted for as long as 3–5 weeks following the last administration of IL-7 in a given cluster. Lastly, the magnitude and frequency of observed increases in sCD127 concentrations was most pronounced in animals that either (C) failed to suppress the virus with ART or (D, F and G) lost virological control, compared to (C) the virologically suppressed animal. The clustered administration of IL-7 is indicated on the x-axis by groups of three arrows labeled as clusters #1–3.</p

Plasma sCD127 concentrations associated with IL-7-induced activation of CD4⁺ T-cells in SIV-infected, ART-treated Rhesus macaques.

<p>The concentration of plasma sCD127 increased as the number of activated CD8⁺ T_EM cells increased in all 4 animals treated with IL-7. Total number of IL-7-treated animals in which T-cell activation data (Ki67 assay) was available: n = 4 (data for the 5^th animal in this group is not available for this parameter of the study). The clustered administration of IL-7 is indicated on the x-axis by groups of three arrows.</p