Hexanic lipidosterolic extract of Serenoa repens inhibits the expression of two key inflammatory mediators, MCP-1/CCL2 and VCAM-1, in vitro.

UNLABELLED: What's known on the subject? and What does the study add? Pervasive inflammatory infiltrates, mainly composed of chronically activated T cells and monocytes/macrophages, have been observed in benign prostatic hyperplasia (BPH). Permixon®, a hexanic lipidosterolic extract of Serenoa repens (hexanic LSESr) used to treat urinary dysfunction in BPH patients, has anti-inflammatory activities. This paper provides new insights into the anti-inflammatory properties of Permixon®. We report that hexanic LSESr inhibits early steps of leukocyte infiltration in vitro by downregulating MCP-1/CCL2 and VCAM-1 expression. OBJECTIVE: To investigate the mechanisms by which hexanic lipidosterolic extract of Serenoa repens (hexanic LSESr) may prevent leukocyte infiltration in benign prostatic hyperplasia by studying its impact on monocyte chemoattractant protein 1/chemokine (C-C motif) ligand 2 (MCP-1/CCL2) and vascular cell adhesion molecule 1 (VCAM-1) expression in vitro. MATERIALS AND METHODS: After pretreatment with hexanic LSESr, human prostate (epithelial and myofibroblastic) cells and vascular endothelial cells were stimulated with proinflammatory cytokines. MCP-1/CCL2 and VCAM-1 mRNA expression was quantified by real-time PCR. ELISA kits were used to determine MCP-1/CCL2 levels in culture supernatants and VCAM-1 expression in living cells. RESULTS: Hexanic LSESr reduced MCP-1/CCL2 mRNA levels in both epithelial (BPH-1) and myofibroblastic (WPMY-1) prostate cell lines. Hexanic LSESr downregulated MCP1/CCL2 secretion by WPMY-1 cells in a concentration-dependent manner, more efficiently than Serenoa repens extracts obtained by supercritical carbon dioxide extraction. Hexanic LSESr inhibited tumour-necrosis-factor-α-induced MCP-1/CCL2 secretion by the human vascular endothelial cell line EAhy.926, as well as surface VCAM-1 protein expression, in a concentration-dependent manner. CONCLUSIONS: Hexanic LSESr impedes key steps of monocyte and T cell attraction and adherence by inhibiting MCP-1/CCL2 and VCAM-1 expression by human prostate and vascular cells in an inflammatory environment. These findings provide new insights into the anti-inflammatory effects of the hexanic lipidosterolic extract of Serenoa repens, Permixon®, in benign prostatic hyperplasia.

Klebsiella pneumoniae-triggered DC recruit human NK cells in a CCR5-dependent manner leading to increased CCL19-responsiveness and activation of NK cells.

Besides their role in destruction of altered self-cells, NK cells have been shown to potentiate T-cell responses by interacting with DC. To take advantage of NK-DC crosstalk in therapeutic DC-based vaccination for infectious diseases and cancer, it is essential to understand the biology of this crosstalk. We aimed to elucidate the in vitro mechanisms responsible for NK-cell recruitment and activation by DC during infection. To mimic bacterial infection, DC were exposed to a membrane fraction of Klebsiella pneumoniae, which triggers TLR2/4. DC matured with these bacterial fragments can actively recruit NK cells in a CCR5-dependent manner. An additional mechanism of DC-induced NK-cell recruitment is characterized by the induction of CCR7 expression on CD56(dim) CD16(+) NK cells after physical contact with membrane fraction of K. pneumoniae-matured DC, resulting in an enhanced migratory responsiveness to the lymph node-associated chemokine CCL19. Bacterial fragment-matured DC do not only mediate NK-cell migration but also meet the prerequisites needed for augmentation of NK-cell cytotoxicity and IFN-γ production, the latter of which contributes to Th1 polarization.

The respiratory syncytial virus G protein conserved domain induces a persistent and protective antibody response in rodents.

Respiratory syncytial virus (RSV) is an important cause of severe upper and lower respiratory disease in infants and in the elderly. There are 2 main RSV subtypes A and B. A recombinant vaccine was designed based on the central domain of the RSV-A attachment G protein which we had previously named G2Na (aa130-230). Here we evaluated immunogenicity, persistence of antibody (Ab) response and protective efficacy induced in rodents by: (i) G2Na fused to DT (Diphtheria toxin) fragments in cotton rats. DT fusion did not potentiate neutralizing Ab responses against RSV-A or cross-reactivity to RSV-B. (ii) G2Nb (aa130-230 of the RSV-B G protein) either fused to, or admixed with G2Na. G2Nb did not induce RSV-B-reactive Ab responses. (iii) G2Na at low doses. Two injections of 3 µg G2Na in Alum were sufficient to induce protective immune responses in mouse lungs, preventing RSV-A and greatly reducing RSV-B infections. In cotton rats, G2Na-induced RSV-reactive Ab and protective immunity against RSV-A challenge that persisted for at least 24 weeks. (iv) injecting RSV primed mice with a single dose of G2Na/Alum or G2Na/PLGA [poly(D,L-lactide-co-glycolide]. Despite the presence of pre-existing RSV-specific Abs, these formulations effectively boosted anti-RSV Ab titres and increased Ab titres persisted for at least 21 weeks. Affinity maturation of these Abs increased from day 28 to day 148. These data indicate that G2Na has potential as a component of an RSV vaccine formulation.

Streptococcus pneumoniae polysaccharides conjugated to the outer membrane protein A from Klebsiella pneumoniae elicit protective antibodies.

Polysaccharides (PSs) derived from Streptococcus pneumoniae include more than 90 serotypes and differ greatly in their immunogenicity. In addition, immunization with PSs does not induce high affinity antibody production and no memory B-cells are generated. Coupling PSs to carrier proteins has been reported to induce B-cell maturation and to install a B-cell memory. As an alternative carrier protein, the outer membrane protein A (OmpA) derived from Klebsiella pneumoniae has been coupled to various PSs. We evaluated the immunogenicity of two PS conjugates, using PS derived from S. pneumoniae types 14 and 19. In this report, we show that anti-PS IgG responses are generated after the conjugation of PSs to P40. In addition, the humoral response generated is able to protect mice from a bacterial challenge. Our results indicate that P40 could be included in the development of new PS conjugate vaccines.

DDA adjuvant induces a mixed Th1/Th2 immune response when associated with BBG2Na, a respiratory syncytial virus potential vaccine.

Human respiratory syncytial virus (hRSV) is one of the most common causes of respiratory infection in infants and the elderly. Previous attempts to vaccinate children against RSV failed and the induction of an aberrant Th2-type immune response was shown to induce severe to fatal pulmonary disease characterised in part by eosinophilia. BBG2Na is a promising human RSV subunit vaccine candidate which successfully passed phase II clinical trials in adults in association with Adju-Phos((R)). However, this formulation is not the most suitable for use in children since aluminium salts are known to induce a Th2-based immune response. In this study, we describe a potent and safe adjuvant formulation for BBG2Na in dimethyldioctadecylammonium bromide (DDA) that induces a mixed Th1/Th2 immune response in BALB/c mice. Furthermore, BBG2Na showed the same protective efficacy against RSV challenge when formulated either in DDA or in alum in mice and cotton rats.

Passive transfer of serum antibodies induced by BBG2Na, a subunit vaccine, in the elderly protects SCID mouse lungs against respiratory syncytial virus challenge.

Respiratory syncytial virus (RSV) is responsible for severe low respiratory tract infections in young infants and the elderly. To investigate whether BBG2Na, a recombinant subunit vaccine comprising aa 130-230 of the RSV G protein, induced protective Abs in subjects over 60 years during phase II clinical trial, pre- and postimmunization sera of individuals immunized with BBG2Na or placebo were transferred into SCID mice before RSV challenge. These sera dose-dependently reduced lung RSV titers. However at some points of serial dilutions, postimmunization sera of BBG2Na-immunized subjects only were significantly more efficient than the corresponding preimmunization sera, in agreement with the induction of an increased Ab response against multiple epitopes on RSV-A G protein. Thus, BBG2Na is immunogenic in the elderly and confers passive protection in mice after serum transfer. To our knowledge, this is the first description of protective Abs induced by a subunit vaccine in human.