Dendritic cells primed with a chimeric plasmid containing HIV-1-gag associated with lysosomal-associated protein-1 (LAMP/gag) is a potential therapeutic vaccine against HIV.

The decline in number and function of T cells is a hallmark of HIV infection, and preservation or restoration of HIV-specific cellular immune response is a major goal of AIDS treatment. Dendritic cells (DCs) play a key role in the initiation and maintenance of the immune response, and their use as a vaccine vehicle is a promising strategy for enhancing vaccine efficacy. We evaluated the potential of DC-mediated immunization with a DNA vaccine consisting of HIV-1-p55gag (gag, group-specific antigen) associated to lysosomal associated protein (LAMP) sequence (LAMP/gag vaccine). Immunization of mice with mouse DCs transfected with LAMP/gag (Lg-mDCs) stimulated more potent B- and T-cell responses than naked DNA or DCs pulsed with inactivated HIV. Anti-Gag antibody levels were sustained for at least 3 mo after immunization, and recall T-cell responses were also strongly detected at this time point. Human DCs transfected with LAMP/gag (Lg-hDCs) were also activated and able to stimulate greater T-cell response than native gag-transfected DCs. Coculture between Lg-hDCs and T lymphocytes obtained from patients with HIV resulted in upregulation of CD38, CD69, HLA-DR, and granzyme B by CD4(+) and CD8(+) T cells, and increased IFN-γ and TNF-α production. These results indicate that the use of LAMP/gag-DC may be an efficient strategy for enhancing immune function in patients with HIV.-Lucas, C. G. D. O., Matassoli, F. L., Peçanha, L. M. T., Santillo, B. T., Oliveira, L. M. D. S., Oshiro, T. M., Marques, E. T. D. A., Jr., Oxenius, A., de Arruda, L. B. Dendritic cells primed with a chimeric plasmid containing HIV-1-gag associated with lysosomal-associated protein-1 (LAMP/gag) is a potential therapeutic vaccine against HIV.

Warifteine, an alkaloid purified from Cissampelos sympodialis, inhibits neutrophil migration in vitro and in vivo.

Cissampelos sympodialis Eichl is a plant from the Northeast and Southeast of Brazil. Its root infusion is popularly used for treatment of inflammatory and allergic diseases. We investigated whether warifteine, its main alkaloid, would have anti-inflammatory effect due to a blockage of neutrophil function. In vivo warifteine treatment inhibited casein-induced neutrophil migration to the peritoneal cavity but did not inhibit neutrophil mobilization from the bone marrow. Analysis of the direct effect of warifteine upon neutrophil adherence and migration in vitro demonstrated that the alkaloid decreased cell adhesion to P and E-selectin-transfected cells. In addition, fLMP-induced neutrophil migration in a transwell system was blocked by warifteine; this effect was mimicked by cAMP mimetic/inducing substances, and warifteine increased intracellular cAMP levels in neutrophils. The production of DNA extracellular traps (NETs) was also blocked by warifteine but there was no alteration on PMA-induced oxidative burst or LPS-stimulated TNF α secretion. Taken together, our data indicate that the alkaloid warifteine is a potent anti-inflammatory substance and that it has an effect on neutrophil migration through a decrease in both cell adhesion and migration.

Synthetic 1,4-pyran naphthoquinones are potent inhibitors of dengue virus replication.

Dengue virus infection is a serious public health problem in endemic areas of the world where 2.5 billion people live. Clinical manifestations of the Dengue infection range from a mild fever to fatal cases of hemorrhagic fever. Although being the most rapidly spreading mosquito-borne viral infection in the world, until now no strategies are available for effective prevention or control of Dengue infection. In this scenario, the development of compounds that specifically inhibit viral replication with minimal effects to the human hosts will have a substantial effect in minimizing the symptoms of the disease and help to prevent viral transmission in the affected population. The aim of this study was to screen compounds with potential activity against dengue virus from a library of synthetic naphthoquinones. Several 1,2- and 1,4-pyran naphthoquinones were synthesized by a three-component reaction of lawsone, aldehyde (formaldehyde or arylaldehydes) and different dienophiles adequately substituted. These compounds were tested for the ability to inhibit the ATPase activity of the viral NS3 enzyme in in vitro assays and the replication of dengue virus in cultured cells. We have identified two 1,4-pyran naphthoquinones, which inhibited dengue virus replication in mammal cells by 99.0% and three others that reduced the dengue virus ATPase activity of NS3 by two-fold in in vitro assays.

Inhibitory effect of the alkaloid warifteine purified from Cissampelos sympodialis on B lymphocyte function in vitro and in vivo.

The aqueous fraction of the ethanolic extract of the plant CISSAMPELOS SYMPODIALIS (Menispermaceae) was previously described to inhibit B cell function. The alkaloid warifteine is the major component of this extract. In the present study we investigated the effect of warifteine on B lymphocyte function and characterized its mechanism of action. Purified splenic murine B lymphocytes were stimulated with either Toll-like receptor (TLR) ligands (LPS, Pam (3)Cys and CpG oligodeoxynucleotides) or anti-IgM antibody and the effect of warifteine on B cell response was investigated. Warifteine inhibited both the proliferative response and immunoglobulin (Ig) secretion induced by these stimuli. Kinetics studies demonstrated that warifteine blocked B cell function even when added after 24 h of a 72 h culture. The inhibitory effect of warifteine was also detected in cultures activated by phorbol myristate acetate and calcium ionophore. We investigated the signal transduction pathways blocked by warifteine. It did not modify the total protein phosphorylation pattern in LPS and anti-IgM-stimulated B cell cultures. It did, however, decrease the rise in intracellular calcium levels, the phosphorylation of the mitogen activated protein kinase (MAPK) ERK and the intranuclear levels of the transcription factor NFkappaB. Warifteine also induced an increase in cAMP and its effect on LPS-induced proliferation was mimicked by the control adenyl cyclase activator forskolin. IN VIVO Ig production induced by the TI-2 antigen TNP-ficoll was also inhibited by warifteine. Taking together, our data suggest that warifteine is a potent inhibitor of B cell response both IN VITRO and IN VIVO and that this effect may be due to the induction of increased intracellular cAMP levels, suggesting that this substance may be useful as a modulator of B cell function.