Emergence of CXCR4-using human immunodeficiency virus type 1 (HIV-1) variants in a minority of HIV-1-infected patients following treatment with the CCR5 antagonist maraviroc is from a pretreatment CXCR4-using virus reservoir

Antagonists of the human immunodeficiency virus type 1 (HIV-1) coreceptor, CCR5, are being developed as the first anti-HIV agents acting on a host cell target. We monitored the coreceptor tropism of circulating virus, screened at baseline for coreceptor tropism, in 64 HIV-1-infected patients who received maraviroc (MVC, UK-427,857) as monotherapy for 10 days. Sixty-two patients harbored CCR5-tropic virus at baseline and had a posttreatment phenotype result. Circulating virus remained CCR5 tropic in 60/62 patients, 51 of whom experienced an HIV RNA reduction from baseline of >1 log(10) copies/ml, indicating that CXCR4-using variants were not rapidly selected despite CCR5-specific drug pressure. In two patients, viral load declined during treatment and CXCR4-using virus was detected at day 11. No pretreatment factor predicted the emergence of CXCR4-tropic virus during maraviroc therapy in these two patients. Phylogenetic analysis of envelope (Env) clones from pre- and posttreatment time points indicated that the CXCR4-using variants probably emerged by outgrowth of a pretreatment CXCR4-using reservoir, rather than via coreceptor switch of a CCR5-tropic clone under selection pressure from maraviroc. Phylogenetic analysis was also performed on Env clones from a third patient harboring CXCR4-using virus prior to treatment. This patient was enrolled due to a sample labeling error. Although this patient experienced no overall reduction in viral load in response to treatment, the CCR5-tropic components of the circulating virus did appear to be suppressed while receiving maraviroc as monotherapy. Importantly, in all three patients, circulating virus reverted to predominantly CCR5 tropic following cessation of maraviroc.     

Tumor therapeutics by design: targeting and activation of death receptors

Due to their strong apoptosis-inducing capacity, the death receptor ligands CD95L, TNF and TRAIL have been widely viewed as potential cancer therapeutics. While clinical data with CD95L and TRAIL are not yet available, TNF is a registered drug, albeit only for loco-regional application in a limited number of indications. The TNF experience has told us that specific delivery and restricted action is a major challenge in the development of multifunctional, pleiotropically acting cytokines into effective cancer therapeutics. Thus, gene-therapeutic approaches and new cytokine variants have been designed over the last 10 years with the aim of increasing anti-tumoral activity and reducing systemic side effects. Here, we present our current view of the therapeutic potential of the death receptor ligands TNF, CD95L and TRAIL and of the progress made towards improving their efficacy by tumor targeting, use of gene therapy and genetic engineering. Results generated with newly designed fusion proteins suggest that enhanced tumor-directed activity and prevention of undesirable actions of death receptor ligands is possible, thereby opening up a useful therapeutic window for all of the death receptor ligands, including CD95L.     

Neisseria meningitidis NadA is a new invasin which promotes bacterial adhesion to and penetration into human epithelial cells

Neisseria meningitidis is a human pathogen, which is a major cause of sepsis and meningitis. The bacterium colonizes the upper respiratory tract of approximately 10% of humans where it lives as a commensal. On rare occasions, it crosses the epithelium and reaches the bloodstream causing sepsis. From the bloodstream it translocates the blood-brain barrier, causing meningitis. Although all strains have the potential to cause disease, a subset of them, which belongs to hypervirulent lineages, causes disease more frequently than others. Recently, we described NadA, a novel antigen of N. meningitidis, present in three of the four known hypervirulent lineages. Here we show that NadA is a novel bacterial invasin which, when expressed on the surface of Escherichia coli, promotes adhesion to and invasion into Chang epithelial cells. Deletion of the N-terminal globular domain of recombinant NadA or pronase treatment of human cells abrogated the adhesive phenotype. A hypervirulent strain of N. meningitidis where the nad A gene was inactivated had a reduced ability to adhere to and invade into epithelial cells in vitro. NadA is likely to improve the fitness of N. meningitidis contributing to the increased virulence of strains that belong to the hypervirulent lineages.     

Biotechnology and vaccines: application of functional genomics to Neisseria meningitidis and other bacterial pathogens

Since its introduction, vaccinology has been very effective in preventing infectious diseases. However, in several cases, the conventional approach to identify protective antigens, based on biochemical, immunological and microbiological methods, has failed to deliver successful vaccine candidates against major bacterial pathogens. The recent development of powerful biotechnological tools applied to genome-based approaches has revolutionized vaccine development, biological research and clinical diagnostics. The availability of a genome provides an inclusive virtual catalogue of all the potential antigens from which it is possible to select the molecules that are likely to be more effective. Here, we describe the use of "reverse vaccinology", which has been successful in the identification of potential vaccines candidates against Neisseria meningitidis serogroup B and review the use of functional genomics approaches as DNA microarrays, proteomics and comparative genome analysis for the identification of virulence factors and novel vaccine candidates. In addition, we describe the potential of these powerful technologies in understanding the pathogenesis of various bacteria.     

Effect of high concentration of Co (II) on Enterobacter liquefaciens strain C-1: a bacterium highly resistant to heavy metals with an unknown genome

Heavy metals are required as nutrients for essential functions in microorganisms. However, higher concentrations of these cations are generally toxic and may produce contrasting effects on living organisms. Enterobacter liquefaciens strain C-1, a bacterium isolated from the Moa mine in Cuba, is able to survive in the presence of high concentrations of heavy metals. The proteomes of Enterobacter liquefaciens strain C-1, grown under aerobic conditions in the presence and absence of Co (II) were compared using two-dimensional gel electrophoresis analysis in the isoelectric point range of 4-7 and the mass range of 15-120 kDa. Significant changes in the expression level (> two-fold) were detected for 13 spots: seven and six were up- and down-regulated, respectively. Because the genome of this bacterium is unknown, identification by peptide mass fingerprinting only succeeded in four cases and most of the cross-species identifications were supported by de novo sequencing of tryptic peptides followed by sequence alignment using the MS BLAST program. Twelve different proteins were identified, ten are involved in cellular antioxidant defence probably induced by the presence of Co (II). This is the first step towards understanding the role of proteins participating in the mechanism of resistance to heavy metals in this bacterium.     

Edaphic races and phylogenetic taxa in the Lasthenia californica complex (Asteraceae: Heliantheae): an hypothesis of parallel evolution

Lasthenia californica sensu Ornduff consists of two races that differ in their flavonoid pigments and edaphic tolerances. Recent phylogenetic studies of Lasthenia have revealed that members of L. californica sensu Ornduff belong to two phylogenetic species. The relationship of the edaphic races to these new species and to each other is the focus of this study. Characterization of flavonoid profiles and phylogenetic placement of 33 populations demonstrates that races and phylogenetic taxa are not concordant, suggesting that one or both edaphic races evolved in parallel in the two clades. We hypothesize an edaphically linked ecological role for flavonoid differences that first revealed the existence of two races.     

Endocytosis by the corneal endothelium. I. Regulation of binding and transport of hemeproteins and peroxidase-conjugated lectins across the tissue

 Binding, internalization, and movement of hemeproteins and peroxidase-conjugated lectins across organ cultured rat corneal endothelia has been investigated. Horseradish peroxidase (HRP) type II, bound to the surface, was minimally internalized and was easily washed off. In contrast, HRP-VI bound and was rapidly internalized. Reaction product was observed in vesicles, endosomes, multivesicular bodies, and extended along the length of the intercellular space (ICS) to Descemet’s membrane. Studies at 4° C indicated HRP-VI bound uniformly along the surface in a punctate fashion. Exposure to polylysine or mannose significantly decreased uptake. Other tracers such as HRP-VIII, -IX, catalase, and microperoxidase exhibited limited uptake by the tissue. However, endothelia vigorously internalized soybean agglutinin (SBA)–HRP, and reaction product was found intracellularly and within the ICS at the cell/Descemet’s membrane interface. Internalization and the appearance of SBA–HRP within the ICS was diminished following polylysine or mannose treatment. Experiments at 4° C indicated that SBA–HRP binding and uptake were temperature sensitive. Wheat germ agglutinin (WGA)–HRP was also strongly endocytosed and reaction product was visualized within vesicles, endosomes, and multivesicular bodies. Although WGA-HRP reaction product was observed within the ICS, none was detected at the level of Descemet’s membrane. The WGA competitive sugar N-acetyl-d-glucosamine, reduced endocytosis, whereas exposure to unlabeled WGA and mannose together reduced uptake. These results indicate endothelia exhibit differential uptake of various hemeproteins and lectins which is dependent on charge, mannose receptors, and appropriate surface sugars. Accepted: 3 Mach 1998     

Human T Cell Leukemia Virus Reactivation with Progression of Adult T-Cell Leukemia-Lymphoma

Background

Human T-cell leukemia virus-associated adult T-cell leukemia-lymphoma (ATLL) has a very poor prognosis, despite trials of a variety of different treatment regimens. Virus expression has been reported to be limited or absent when ATLL is diagnosed, and this has suggested that secondary genetic or epigenetic changes are important in disease pathogenesis.

Methods and Findings

We prospectively investigated combination chemotherapy followed by antiretroviral therapy for this disorder. Nineteen patients were prospectively enrolled between 2002 and 2006 at five medical centers in a phase II clinical trial of infusional chemotherapy with etoposide, doxorubicin, and vincristine, daily prednisone, and bolus cyclophosphamide (EPOCH) given for two to six cycles until maximal clinical response, and followed by antiviral therapy with daily zidovudine, lamivudine, and alpha interferon-2a for up to one year. Seven patients were on study for less than one month due to progressive disease or chemotherapy toxicity. Eleven patients achieved an objective response with median duration of response of thirteen months, and two complete remissions. During chemotherapy induction, viral RNA expression increased (median 190-fold), and virus replication occurred, coincident with development of disease progression.

Conclusions

EPOCH chemotherapy followed by antiretroviral therapy is an active therapeutic regimen for adult T-cell leukemia-lymphoma, but viral reactivation during induction chemotherapy may contribute to treatment failure. Alternative therapies are sorely needed in this disease that simultaneously prevent virus expression, and are cytocidal for malignant cells.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00041327","term_id":"NCT00041327"}}NCT00041327