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Low-temperature nitrogen plasma ( LTNP) was used to wither green tea leaf to study its effect on the polyphenol content. Using a dielectric barrier discharge chamber to provide the LTNP environment, green tea leaf was withered at various withering times. Made tea samples indicated that LTNP had an effect on polyphenol content. The highest polyphenol content of 78.56 mg g−1 in made tea was attained in 1 h after which it showed a decreasing trend with increasing retention time. For comparison purposes, green tea leaf was also withered in nonplasma environments. Highest polyphenol content of 133.4 mg g−1 in made tea was attained in a sample withered anaerobically in nitrogen gas at room temperature and atmospheric pressure for 18 h. In another sample, green tea leaf was directly macerated and dried without withering and fermenting and had polyphenol content of 101.91 mg g−1 in made tea. These contents were compared with green tea 4, purple tea and oolong tea that are currently manufactured in Kenya. [ABSTRACT FROM AUTHOR]

Introduction: HIV‐1‐associated CD4+ T‐cell depletion is a consequence of uninfected cell death. Nef is one of the viral factors that trigger apoptosis on bystander cells, though the plasma Nef levels do not correlate with Th lymphocytes counts. The aim of our study was to evaluate whether anti‐Nef antibodies were involved in paediatric AIDS development and whether they can prevent the CD4+ T‐cell depletion in vertically infected children. Methods: Two hundred and seventy three HIV‐1 vertically infected children seen at Garrahan Paediatric Hospital were randomly included in the study, adding 13 selected cases: seven LTNP (long‐term non‐progressors) and six RP (rapid progressors) children (ntotal=286). Specific anti‐HIV‐1‐Nef antibodies were titrated by indirect ELISA and compared between groups. The plasma blocking effect on Nef‐dependent cytotoxicity was evaluated in Jurkat cells using recombinant Nef as apoptotic stimulus and patient plasmas as blockers, measuring the apoptotic levels using Annexin‐V stain and flow cytometry. Results: Only 63.4% of the patients had specific anti‐Nef antibodies, and the levels of anti‐Nef antibodies found in the selected LTNPs plasmas were always significantly higher (p=1.55×10−4) than those in RPs or general HIV‐1+ paediatric populations. The LTNPs’ plasma had a strong inhibitory effect on Nef‐dependent cytotoxicity even at high dilutions, while RP plasmas had little or no effect on Nef‐induced apoptosis. Discussion and conclusions: High anti‐Nef antibody levels are associated and predict slow or non‐progression to AIDS in vertically HIV‐1‐infected children. They could be an efficient tool in preventing Nef‐associated bystander effect, preserving CD4+ T‐cells and the immune function in the context of paediatric HIV‐1 infection. [ABSTRACT FROM AUTHOR]

Background We hypothesized that there may be a correlation between the interleukin-7 (IL-7)/IL-7 receptor (IL-7R) regulatory system and parameters of T-cell homeostasis in HIV-infected long-term nonprogressors (LTNPs) as compared with patients with disease progression. Methods The possibility of a correlation between T-cell homeostatic parameters and IL-7/IL-7R was investigated in 22 LTNPs (CD4 count ≥500 cells/μL for >10 years) vs. HIV-positive patients at different disease stages [12 early: CD4 count ≥400 cells/μL; 15 late (AIDS-presenters): CD4 count ≤150 cells/μL]. Results Compared with early-stage HIV-positive patients, LTNPs displayed a higher circulating IL-7 concentration ( P=0.05), which was positively associated with higher IL-7Rα expression and a higher T-cell receptor excision circle (TREC) content specifically within CD4 cells ( P<0.05). Compared with late-stage disease patients, early-stage disease patients displayed a lower IL-7 concentration ( P<0.01) and higher percentages of IL-7Rα+ CD4 and CD8 cells ( P=0.05). IL-7 was positively correlated with the percentage of TREC+ CD4 cells ( P<0.01), which translated into a higher percentage of naïve CD4 cells in early-stage disease patients than in late-stage disease patients; however, the CD4 cells in early-stage disease patients were less enriched in recent thymic emigrants (RTEs) compared with LTNPs ( P<0.05). In late-stage AIDS-developing patients, substantially increased IL-7 was correlated with a decreased percentage of IL-7Rα+ CD4 cells ( P=0.01), which resulted in these patients having a significantly lower percentage of naïve T cells ( P<0.01) and a significantly lower content of TREC ( P<0.01) than the other patients. Conclusions The maintenance of high CD4 cell counts in LTNPs was associated with a specific IL-7/IL-7R pattern characterized by increased IL-7 and highest IL-7Rα-expressing CD4 cells relative to other patients. Compared with patients with late-stage disease, LTNPs displayed a phenotypically naïve, less activated CD4 cell pool highly enriched in RTEs, suggesting the existence of a compensatory IL-7-mediated pathway specifically sustaining peripheral CD4 counts. [ABSTRACT FROM AUTHOR]

NAb have been considered to be an important component of a protective immune response to HIV-1, yet the relationship between the capacity of HIV-1 NAb, the conserved neutralization epitopes and disease progression has been unclear. To gain a better understanding of the protective roles that NAb and conserved neutralization epitopes could play in LTNP, twenty-eight HIV-1-infected subjects were investigated by evaluation of the concentrations of HIV-1 NAb and conserved neutralization epitopes, using single-round PBMC neutralization assay and sequencing. Our study revealed that the concentration of NAb in LTNP was significantly higher than that in subjects with asymptomatic HIV ( P < 0.05) and AIDS ( P < 0.01). No amino acids substitutions were found in the conserved epitopes of the HIV-1 gp120 region in LTNP, whereas the viruses circulating both in persons with asymptomatic HIV and those with AIDS had amino acid substitutions in their conserved neutralization epitopes. This study suggests that high levels of NAb and stable epitopes in gp120 could play a crucial role in protection against disease progression. [ABSTRACT FROM AUTHOR]