Development of a pseudo-typed virus particle based method to determine the efficacy of virucidal agents.

The ongoing Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic has highlighted the threat that viral outbreaks pose to global health. A key tool in the arsenal to prevent and control viral disease outbreaks is disinfection of equipment and surfaces with formulations that contain virucidal agents (VA). However, assessment of the efficacy of virus inactivation often requires live virus assays or surrogate viruses such as Modified Vaccinia Virus Ankara (MVA), which can be expensive, time consuming and technically challenging.

Personal care formulations demonstrate virucidal efficacy against multiple SARS-CoV-2 variants of concern: Implications for hand hygiene and public health.

Despite considerable progress being made on vaccine roll out, practicing proper hand hygiene has been advocated as a consistent precautionary intervention against the circulating and emerging variants of SARS-CoV-2. Two variants of concern, namely beta and delta, have been shown to exhibit enhanced transmissibility, high viral load, and ability to escape antibody-mediated neutralization. In this report we have empirically determined the efficacy of selected personal care formulations from Unilever in inactivating the beta and delta variants of SARS-CoV-2 under simulated real-life conditions.

CPC-containing oral rinses inactivate SARS-CoV-2 variants and are active in the presence of human saliva.

The importance of human saliva in aerosol-based transmission of SARS-CoV-2 is now widely recognized. However, little is known about the efficacy of virucidal mouthwash formulations against emergent SARS-CoV-2 variants of concern and in the presence of saliva. Mouthwashes containing virucidal actives will have similar inactivation effects against multiple SARS-CoV-2 variants of concern and will retain efficacy in the presence of human saliva.

Antiviral efficacy of personal care formulations against Severe Acute Respiratory Syndrome Coronavirus 2.

Background: Non-therapeutic interventions such as practicing good hand hygiene continue to be the mainstay of protection from SARS-CoV-2 and other emerging respiratory viruses.

Methods: We have evaluated a range of commercially available personal care products including soaps, handwash liquids and alcohol-based hand sanitizers for antiviral efficacy against a clinical isolate of SARS-CoV-2 using internationally accepted standardized protocols at user-relevant contact time-points and product dilutions.

Results: All the tested products resulted in 3 to 4 log reduction of SARS-CoV-2 titer.

Trisomy 21 mid-trimester amniotic fluid induced pluripotent stem cells maintain genetic signatures during reprogramming: implications for disease modeling and cryobanking.

Trisomy 21 is the most common chromosomal abnormality and is associated primarily with cardiovascular, hematological, and neurological complications. A robust patient-derived cellular model is necessary to investigate the pathophysiology of the syndrome because current animal models are limited and access to tissues from affected individuals is ethically challenging. We aimed to derive induced pluripotent stem cells (iPSCs) from trisomy 21 human mid-trimester amniotic fluid stem cells (AFSCs) and describe their hematopoietic and neurological characteristics.

Gene correction of induced pluripotent stem cells derived from a murine model of X-linked chronic granulomatous disorder.

Gene therapy presents an attractive alternative to allogeneic haematopoietic stem cell transplantation (HSCT) for treating patients suffering from primary immunodeficiency disorder (PID). The conceptual advantage of gene correcting a patient's autologous HSCs lies in minimizing or completely avoiding immunological complications arising from allogeneic transplantation while conferring the same benefits of immune reconstitution upon long-term engraftment. Clinical trials targeting X-linked chronic granulomatous disorder (X-CGD) have shown promising results in this context.

Gene therapy for PIDs: progress, pitfalls and prospects.

Substantial progress has been made in the past decade in treating several primary immunodeficiency disorders (PIDs) with gene therapy. Current approaches are based on ex-vivo transfer of therapeutic transgene via viral vectors to patient-derived autologous hematopoietic stem cells (HSCs) followed by transplantation back to the patient with or without conditioning. The overall outcome from all the clinical trials targeting different PIDs has been extremely encouraging but not without caveats.

High plasticity of pediatric adipose tissue-derived stem cells: too much for selective skeletogenic differentiation?

Stem cells derived from adipose tissue are a potentially important source for autologous cell therapy and disease modeling, given fat tissue accessibility and abundance. Critical to developing standard protocols for therapeutic use is a thorough understanding of their potential, and whether this is consistent among individuals, hence, could be generally inferred. Such information is still lacking, particularly in children.

Brief report: self-organizing neuroepithelium from human pluripotent stem cells facilitates derivation of photoreceptors.

Retinitis pigmentosa, other inherited retinal diseases, and age-related macular degeneration lead to untreatable blindness because of the loss of photoreceptors. We have recently shown that transplantation of mouse photoreceptors can result in improved vision. It is therefore timely to develop protocols for efficient derivation of photoreceptors from human pluripotent stem (hPS) cells.

Valproic acid confers functional pluripotency to human amniotic fluid stem cells in a transgene-free approach.

Induced pluripotent stem cells (iPSCs) with potential for therapeutic applications can be derived from somatic cells via ectopic expression of a set of limited and defined transcription factors. However, due to risks of random integration of the reprogramming transgenes into the host genome, the low efficiency of the process, and the potential risk of virally induced tumorigenicity, alternative methods have been developed to generate pluripotent cells using nonintegrating systems, albeit with limited success. Here, we show that c-KIT+ human first-trimester amniotic fluid stem cells (AFSCs) can be fully reprogrammed to pluripotency without ectopic factors, by culture on Matrigel in human embryonic stem cell (hESC) medium supplemented with the histone deacetylase inhibitor (HDACi) valproic acid (VPA).

Functional human artificial chromosomes are generated and stably maintained in human embryonic stem cells.

We present a novel and efficient non-integrating gene expression system in human embryonic stem cells (hESc) utilizing human artificial chromosomes (HAC), which behave as autonomous endogenous host chromosomes and segregate correctly during cell division. HAC are important vectors for investigating the organization and structure of the kinetochore, and gene complementation. HAC have so far been obtained in immortalized or tumour-derived cell lines, but never in stem cells, thus limiting their potential therapeutic application.

Generation of functional neutrophils from a mouse model of X-linked chronic granulomatous disorder using induced pluripotent stem cells.

Murine models of human genetic disorders provide a valuable tool for investigating the scope for application of induced pluripotent stem cells (iPSC). Here we present a proof-of-concept study to demonstrate generation of iPSC from a mouse model of X-linked chronic granulomatous disease (X-CGD), and their successful differentiation into haematopoietic progenitors of the myeloid lineage. We further demonstrate that additive gene transfer using lentiviral vectors encoding gp91(phox) is capable of restoring NADPH-oxidase activity in mature neutrophils derived from X-CGD iPSC.

Lentivirus-mediated reprogramming of somatic cells in the absence of transgenic transcription factors.

Retroviral vectors remain the most efficient and widely applied system for induction of pluripotency. However, mutagenic effects have been documented in both laboratory and clinical gene therapy studies, principally as a result of dysregulated host gene expression in the proximity of defined integration sites. Here, we report that cells with characteristics of pluripotent stem cells can be produced from normal human fibroblasts in the absence of reprogramming transcription factors (TFs) during lentiviral (LV) vector-mediated gene transfer.

Nonintegrating lentivector vaccines stimulate prolonged T-cell and antibody responses and are effective in tumor therapy.

Lentiviral vectors (lentivectors) are effective for stimulation of cell-mediated and humoral immunity following subcutaneous and intramuscular immunization. However, lentivector genome integration carries a risk of perturbation of host gene expression. Here, we demonstrate that lentivectors with multiple mutations that prevent integration are also effective immunogens.

Proviral progeny of heterodimeric virions reveal a high crossover rate for human immunodeficiency virus type 2.

Human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS in humans, exhibits a very high rate of recombination. Bearing in mind the significant epidemiological and clinical contrast between HIV-2 and HIV-1 as well as the critical role that recombination plays in viral evolution, we examined the nature of HIV-2 recombination. Towards this end, a strategy was devised to measure the rate of crossover of HIV-2 by evaluating recombinant progeny produced exclusively by heterodimeric virions.

A HIV-2-based self-inactivating vector for enhanced gene transduction.

The employment of HIV-1-based vectors in clinical trials is controversial mainly due to the lethal nature of the virus. HIV-2 is less pathogenic in nature and therefore is likely to be safer for vector design and production. We developed HIV-2-based self-inactivating vectors in which 520 bp out of 554 bp of the viral U3 was deleted.

High rate of genetic recombination in murine leukemia virus: implications for influencing proviral ploidy.

A significant difference in the recombination rates between human immunodeficiency virus type 1 (HIV-1) and the gammaretroviruses was previously reported, with the former being 10 to 100 times more recombinogenic. It is possible that preferential copackaging of homodimers in the case of gammaretroviruses, like murine leukemia virus (MLV), led to the underestimation of their rates of recombination. To reexamine the recombination rates for MLV, experiments were performed to control for nonrandom copackaging of viral RNA, and it was found that MLV and HIV-1 exhibit similar crossover rates.