High surface IgM levels associate with shorter response to ibrutinib and BTK bypass in patients with CLL.

Chronic lymphocytic leukemia (CLL) cells have variably low surface IgM (sIgM) levels/signaling capacity, influenced by chronic antigen engagement at tissue sites. Within these low levels, CLL with relatively high sIgM (CLLhigh) progresses more rapidly than CLL with low sIgM (CLLlow). During ibrutinib therapy, surviving CLL cells redistribute into the peripheral blood and can recover sIgM expression.

Immune responses against SARS-CoV-2 variants after two and three doses of vaccine in B-cell malignancies: UK PROSECO study.

Patients with hematological malignancies are at increased risk of severe COVID-19 outcomes due to compromised immune responses, but the insights of these studies have been compromised due to intrinsic limitations in study design. Here we present the PROSECO prospective observational study ( NCT04858568 ) on 457 patients with lymphoma that received two or three COVID-19 vaccine doses. We show undetectable humoral responses following two vaccine doses in 52% of patients undergoing active anticancer treatment.

SHAPE-directed discovery of potent shRNA inhibitors of HIV-1.

The RNA interference (RNAi) pathway can be exploited using short hairpin RNAs (shRNAs) to durably inactivate pathogenic genes. Prediction of optimal target sites is notoriously inaccurate and current approaches applied to HIV-1 show weak correlations with virus inhibition. In contrast, using a high-content model for disrupting pre-existing intramolecular structure in the HIV-1 RNA, as achievable using high-resolution SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) chemical probing information, we discovered strong correlations between inhibition of HIV-1 production in a quantitative cell-based assay and very simple thermodynamic features in the target RNA.

RNAi-inducing lentiviral vectors for anti-HIV-1 gene therapy.

RNA interference (RNAi)-based gene therapy for the treatment of HIV-1 infection provides a novel antiviral approach. For delivery of RNAi inducers to CD4+ T cells or CD34+ blood stem cells, lentiviral vectors are attractive because of their ability to transduce nondividing cells. In addition, lentiviral vectors allow stable transgene expression by inserting their cargo into the host cell genome.

Anticipating and blocking HIV-1 escape by second generation antiviral shRNAs.

Background: RNA interference (RNAi) is an evolutionary conserved gene silencing mechanism that mediates the sequence-specific breakdown of target mRNAs. RNAi can be used to inhibit HIV-1 replication by targeting the viral RNA genome. However, the error-prone replication machinery of HIV-1 can generate RNAi-resistant variants with specific mutations in the target sequence.

Titers of lentiviral vectors encoding shRNAs and miRNAs are reduced by different mechanisms that require distinct repair strategies.

RNAi-based gene therapy is a powerful approach to treat viral infections because of its high efficiency and sequence specificity. The HIV-1-based lentiviral vector system is suitable for the delivery of RNAi inducers to HIV-1 susceptible cells due to its ability to transduce nondividing cells, including hematopoietic stem cells, and its ability for stable transgene delivery into the host cell genome. However, the presence of anti-HIV short hairpin RNA (shRNA) and microRNA (miRNA) cassettes can negatively affect the lentiviral vector titers.

Lentiviral vector engineering for anti-HIV RNAi gene therapy.

RNA interference or RNAi-based gene therapy for the treatment of HIV-1 infection has recently emerged as a highly effective antiviral approach. The lentiviral vector system is a good candidate for the expression of antiviral short hairpin RNAs (shRNA) in HIV-susceptible cells. However, this strategy can give rise to vector problems because the anti-HIV shRNAs can also target the HIV-based lentiviral vector system.

Optimization of shRNA inhibitors by variation of the terminal loop sequence.

Gene silencing by RNA interference (RNAi) can be achieved by intracellular expression of a short hairpin RNA (shRNA) that is processed into the effective small interfering RNA (siRNA) inhibitor by the RNAi machinery. Previous studies indicate that shRNA molecules do not always reflect the activity of corresponding synthetic siRNAs that attack the same target sequence. One obvious difference between these two effector molecules is the hairpin loop of the shRNA.

Combinatorial RNAi against HIV-1 using extended short hairpin RNAs.

RNA interference (RNAi) is a widely used gene suppression tool that holds great promise as a novel antiviral approach. However, for error-prone viruses including human immunodeficiency virus type 1(HIV-1), a combinatorial approach against multiple conserved sequences is required to prevent the emergence of RNAi-resistant escape viruses. Previously, we constructed extended short hairpin RNAs (e-shRNAs) that encode two potent small interfering RNAs (siRNAs) (e2-shRNAs).

Stringent testing identifies highly potent and escape-proof anti-HIV short hairpin RNAs.

Background: RNA interference (RNAi) is a cellular mechanism that can be induced by small interfering RNAs to mediate sequence-specific gene silencing by cleavage of the targeted mRNA. RNAi can be used as an antiviral approach to silence the human immunodeficiency virus type 1 (HIV-1) through stable expression of short hairpin RNAs (shRNAs). Previously, we used a co-transfection assay in which shRNA constructs were transfected with an HIV-1 molecular clone to identify 20 shRNA inhibitors that target highly conserved HIV-1 sequences.

Towards a durable RNAi gene therapy for HIV-AIDS.

Background: RNA interference (RNAi) can be employed as a potent antiviral mechanism.

Objective: To discuss RNAi approaches to target pathogenic human viruses causing acute or chronic infections, in particular RNAi gene therapy against HIV-1.

Methods: A review of relevant literature.

Probing the sequence space available for HIV-1 evolution.

We designed a novel experimental approach to probe the sequence space available for HIV-1 evolution. Selective pressure was put on conserved HIV-1 genomic sequences by means of RNA interference (RNAi). Virus escape was monitored in many parallel cultures, and we scored the mutations selected in the RNAi target sequences.

Evaluation of safety and efficacy of RNAi against HIV-1 in the human immune system (Rag-2(-/-)gammac(-/-)) mouse model.

RNA interference (RNAi) gene therapy against HIV-1 by stable expression of antiviral short hairpin RNAs (shRNAs) can potently inhibit viral replication in T cells. Recently, a mouse model with a human immune system (HIS) was developed that can be productively infected with HIV-1. In this in vivo model, in which Rag-2(-/-)gamma(c)(-/-) mice are engrafted with human CD34(+)CD38(-) hematopoietic precursor cells, we evaluated an anti-HIV RNAi gene therapy.

Inhibition of HIV-1 by multiple siRNAs expressed from a single microRNA polycistron.

RNA interference (RNAi) is a powerful approach to inhibit human immunodeficiency virus type 1 (HIV-1) replication. However, HIV-1 can escape from RNAi-mediated antiviral therapy by selection of mutations in the targeted sequence. To prevent viral escape, multiple small interfering RNAs (siRNAs) against conserved viral sequences should be combined.

Lentiviral Vector Design for Multiple shRNA Expression and Durable HIV-1 Inhibition.

Human immunodeficiency virus type 1 (HIV-1) replication in T cells can be inhibited by RNA interference (RNAi) through short hairpin RNA (shRNA) expression from a lentiviral vector. However, for the development of a durable RNAi-based gene therapy against HIV-1, multiple shRNAs need to be expressed simultaneously in order to avoid viral escape. In this study, we tested a multiple shRNA expression strategy for different shRNAs using repeated promoters in a lentiviral vector.

Lentiviral vector design for multiple shRNA expression and durable HIV-1 inhibition.

Human immunodeficiency virus type 1 (HIV-1) replication in T cells can be inhibited by RNA interference (RNAi) through short hairpin RNA (shRNA) expression from a lentiviral vector. However, for the development of a durable RNAi-based gene therapy against HIV-1, multiple shRNAs need to be expressed simultaneously in order to avoid viral escape. In this study, we tested a multiple shRNA expression strategy for different shRNAs using repeated promoters in a lentiviral vector.

Human immunodeficiency virus type 1 escape is restricted when conserved genome sequences are targeted by RNA interference.

RNA interference (RNAi) is a cellular mechanism in which small interfering RNAs (siRNAs) mediate sequence-specific gene silencing by cleaving the targeted mRNA. RNAi can be used as an antiviral approach to silence the human immunodeficiency virus type 1 (HIV-1) through stable expression of short-hairpin RNAs (shRNAs). We previously reported efficient HIV-1 inhibition by an shRNA against the nonessential nef gene but also described viral escape by mutation or deletion of the nef target sequence.

Lentiviral vectors that carry anti-HIV shRNAs: problems and solutions.

Background: HIV-1 replication can be inhibited with RNA interference (RNAi) by expression of short hairpin RNA (shRNA) from a lentiviral vector. Because lentiviral vectors are based on HIV-1, viral sequences in the vector system are potential targets for the antiviral shRNAs. Here, we investigated all possible routes by which shRNAs can target the lentiviral vector system.

Silencing of HIV-1 with RNA interference: a multiple shRNA approach.

Double-stranded RNA can induce gene silencing via a process known as RNA interference (RNAi). Previously, we have shown that stable expression of a single shRNA targeting the HIV-1 Nef gene strongly inhibits HIV-1 replication. However, this was not sufficient to maintain inhibition.

The virion-associated incoming HIV-1 RNA genome is not targeted by RNA interference.

Background: RNA interference (RNAi) has proven to be a powerful tool to suppress gene expression and can be used as a therapeutic strategy against human pathogenic viruses such as human immunodeficiency virus type 1 (HIV-1). Theoretically, RNAi-mediated inhibition can occur at two points in the replication cycle, upon viral entry before reverse transcription of the RNA genome, and on the newly transcribed viral RNA transcripts. There have been conflicting results on whether RNAi can target the RNA genome of infecting HIV-1 particles.

Histatin 5-derived peptide with improved fungicidal properties enhances human immunodeficiency virus type 1 replication by promoting viral entry.

Antimicrobial peptides are found in a number of body compartments and are secreted at mucosal surfaces, where they form part of the innate immune system. Many of these small peptides have a broad spectrum of inhibitory activity against bacteria, fungi, parasites, and viruses. Generally, the peptide's mode of action is binding and disruption of membranes due to its amphipathic properties.

Inhibition of human immunodeficiency virus type 1 by RNA interference using long-hairpin RNA.

Inhibition of virus replication by means of RNA interference has been reported for several important human pathogens, including human immunodeficiency virus type 1 (HIV-1). RNA interference against these pathogens has been accomplished by introduction of virus-specific synthetic small interfering RNAs (siRNAs) or DNA constructs encoding short-hairpin RNAs (shRNAs). Their use as therapeutic antiviral against HIV-1 is limited, because of the emergence of viral escape mutants.