Production of lentiviral vectors with enhanced efficiency to target dendritic cells by attenuating mannosidase activity of mammalian cells

<p>Abstract</p> <p>Background</p> <p>Dendritic cells (DCs) are antigen-presenting immune cells that interact with T cells and have been widely studied for vaccine applications. To achieve this, DCs can be manipulated by lentiviral vectors (LVs) to express antigens to stimulate the desired antigen-specific T cell response, which gives this approach great potential to fight diseases such as cancers, HIV, and autoimmune diseases. Previously we showed that LVs enveloped with an engineered Sindbis virus glycoprotein (SVGmu) could target DCs through a specific interaction with DC-SIGN, a surface molecule predominantly expressed by DCs. We hypothesized that SVGmu interacts with DC-SIGN in a mannose-dependent manner, and that an increase in high-mannose structures on the glycoprotein surface could result in higher targeting efficiencies of LVs towards DCs. It is known that 1-deoxymannojirimycin (DMJ) can inhibit mannosidase, which is an enzyme that removes high-mannose structures during the glycosylation process. Thus, we investigated the possibility of generating LVs with enhanced capability to modify DCs by supplying DMJ during vector production.</p> <p>Results</p> <p>Through western blot analysis and binding tests, we were able to infer that binding of SVGmu to DC-SIGN is directly related to amount of high-mannose structures on SVGmu. We also found that the titer for the LV (FUGW/SVGmu) produced with DMJ against 293T.DCSIGN, a human cell line expressing the human DC-SIGN atnibody, was over four times higher than that of vector produced without DMJ. In addition, transduction of a human DC cell line, MUTZ-3, yielded a higher transduction efficiency for the LV produced with DMJ.</p> <p>Conclusion</p> <p>We conclude that LVs produced under conditions with inhibited mannosidase activity can effectively modify cells displaying the DC-specific marker DC-SIGN. This study offers evidence to support the utilization of DMJ in producing LVs that are enhanced carriers for the development of DC-directed vaccines.</p

Quantifying the Impact of Immune History and Variant on SARS-CoV-2 Viral Kinetics and Infection Rebound: A Retrospective Cohort Study

BACKGROUND: The combined impact of immunity and SARS-CoV-2 variants on viral kinetics during infections has been unclear. METHODS: We characterized 1,280 infections from the National Basketball Association occupational health cohort identified between June 2020 and January 2022 using serial RT-qPCR testing. Logistic regression and semi-mechanistic viral RNA kinetics models were used to quantify the effect of age, variant, symptom status, infection history, vaccination status and antibody titer to the founder SARS-CoV-2 strain on the duration of potential infectiousness and overall viral kinetics. The frequency of viral rebounds was quantified under multiple cycle threshold (Ct) value-based definitions. RESULTS: Among individuals detected partway through their infection, 51.0% (95% credible interval [CrI]: 48.3-53.6%) remained potentially infectious (Ct CONCLUSIONS: SARS-CoV-2 viral kinetics are partly determined by immunity and variant but dominated by individual-level variation. Since booster vaccination protects against infection, longer clearance times for BA.1-infected, boosted individuals may reflect a less effective immune response, more common in older individuals, that increases infection risk and reduces viral RNA clearance rate. The shifting landscape of viral kinetics underscores the need for continued monitoring to optimize isolation policies and to contextualize the health impacts of therapeutics and vaccines. FUNDING: Supported in part by CDC contract #200-2016-91779, a sponsored research agreement to Yale University from the National Basketball Association contract #21-003529, and the National Basketball Players Association

Virus-Receptor Mediated Transduction of Dendritic Cells by Lentiviruses Enveloped with Glycoproteins Derived from Semliki Forest Virus

Lentiviruses have recently attracted considerable interest for their potential as a genetic modification tool for dendritic cells (DCs). In this study, we explore the ability of lentiviruses enveloped with alphaviral envelope glycoproteins derived from Semliki Forest virus (SFV) to mediate transduction of DCs. We found that SFV glycoprotein (SFV-G)-pseudotyped lentiviruses use C-type lectins (DC-SIGN and L-SIGN) as attachment factors for transduction of DCs. Importantly, SFV-G pseudotypes appear to have enhanced transduction towards C-type lectin-expressing cells when produced under conditions limiting glycosylation to simple high-mannose, N-linked glycans. These results, in addition to the natural DC tropism of SFV-G, offer evidence to support the use of SFV-G-bearing lentiviruses to genetically modify DCs for the study of DC biology and DC-based immunotherapy

2009

ABSTRACT © F e r r a t a S t o r t i F o u n d a t i o n BCL2 translocations are more frequently found in the GCB subtype, whereas 18q21 locus amplification is more common in the ABC subtype of DLBCL. 3, Design and Methods Patients We studied 327 cases of previously untreated de novo DLBCL, diagnosed between January 2002 and October 2009, and collected as part of the International DLBCL Rituxan-CHOP Consortium Program Study. These cases were analyzed for Bcl-2 protein expression, and BCL2 and MYC gene abnormalities, and gene expression profiling (GEP) was performed. All cases were reviewed by a group of hematopathologists (SMM, MAP, MBM, AT, and KHY), and the diagnoses were confirmed based on World Health Organization classification criteria. Patients with transformation from low grade lymphoma, those with composite follicular lymphoma, primary mediastinal large B-cell lymphoma, primary cutaneous and primary central nervous system DLBCL were excluded from the analysis due to the unique biological features of these types of lymphoma. All patients were adults who were negative for human immunodeficiency virus and had sufficient clinical data and clinical follow-up. Patients in this study were treated with R-CHOP (n=291, 89%) or R-CHOP-like regimens (n=36, 11%; CHOP scheme adopting different anthracyclines i.e. novantrone or epirubicin). All patients with advanced stage disease received six (92%) or eight (8%) cycles, every 21 days, with or without radiotherapy for residual disease or initial bulky disease; localized cases received at least three cycles followed by radiotherapy or six cycles without radiotherapy. The current study was approved by each of the participating centers&apos; Institutional Review Boards, and the overall collaborative study was approved by the Institutional Review Board at The University of Texas MD Anderson Cancer Center in Houston, Texas, USA. Immunohistochemistry for Bcl-2 and cut-off determination Bcl-2 protein expression was evaluated in all patients using a monoclonal anti-Bcl-2 antibody (Clone-124, Dako, Carpinteria, CA, USA) and standard immunohistochemical methods. The formalin-fixed, paraffin-embedded tissue slides underwent deparaffinization and heat-induced antigen retrieval techniques. An endogenous biotin-blocking kit (Ventana) was used to decrease background staining. Following antigen retrieval and primary antibody incubation, the reaction was completed in a Ventana ES instrument using a diaminobenzidine immunoperoxidase detection kit (Ventana). Immunoreactivity was determined without knowledge of the patients&apos; survival, clinical data, or GEP data. The samples were analyzed independently by a group of four hematopathologists/pathologists in addition to the hematopathologist of each of the contributing centers, and disagreements were resolved by joint review at a multi-headed microscope. An average of 300-400 cells in four to five fields were counted in the tissue microarray cores. A percentage of tumor cell staining ≥50% was considered positive after receiver operating characteristic (ROC) curve analysis was implemented to assess the discriminatory accuracy of Bcl-2 protein in recognizing patients with different overall survival (OS) and progression-free survival (PFS). The 50% value was established from the analysis of the area under the ROC curve (AUROC) and had the maximum specificity and sensibility for OS and PFS discrimination in our patients (AUROC=0.564, P=0.017 for OS and AUROC=0.564, P=0.015 for PFS). 31 Gene expression profiling analysis RNA was extracted from 327 formalin-fixed, paraffin-embedded tissue samples using a HighPure Paraffin RNA Extraction Kit (Roche Applied Science). Fifty nanograms of RNA were transcribed into cDNA, linearly amplified using the WT-Ovation™ FFPE System (Nugen), and biotin-labeled using FL-Ovation™ cDNA Biotin Module V2 (Nugen) in all cases. For GeneChip hybridization, 5 μg of WT-Ovation amplified cDNA were applied to HG-U133 Plus 2.0 GeneChips (Affymetrix) and hybridized overnight. GeneChips were washed, stained, and scanned using the Fluidic Station 450 and GeneChip Scanner 3000 (Affymetrix) according to the manufacturer&apos;s recommendations. For data analysis and classification, the microarray DQN (trimmed mean of differences of perfect match and mismatch intensities with quantile normalization) signals were generated and normalized to the quantiles of beta distribution with parameters p=1.2 and q=3 as previously described. 32 A Bayesian model was also utilized to determine the class probability. The classification model was built on the 47 paired formalin-fixed, paraffin-embedded tissue sample dataset previously generated with a confidence rate of 90-100% in fresh frozen tissue and 92-100% in formalin-fixed, paraffinembedded tissue. The same methodology developed during this study has been validated and demonstrated to be applicable by using the LLMPP dataset in the Gene Expression Omnibus (GEO) database GSE#10846 that has 181 CHOP-treated and 233 R-CHOP-treated DLBCL patients with fresh-frozen samples. 3, Validation set To validate our observations in predicting survival in an independent series of cases, we analyzed a second group of 120 archival DLBCL cases studied similarly to the first cohort except for MYC analysis that was not available (GCB 49%, ABC 40%, unclassified 11%; BCL2 translocations in 18%; Bcl-2 overexpression in 54%). All these patients had been treated with R-CHOP and the same selection criteria as those for the first cohort were applied. The clinical characteristics at presentation of the patients in the validation set were not significantly different from those of the patients in the test set. Statistical analysis Following pre-defined criteria, 33 PFS was measured from the time of diagnosis to the time of progression or death from any cause. OS was measured from the time of diagnosis to last followup or death from any cause. Only patients with a follow-up of longer than 12 months were included in the survival analysis. The actuarial probabilities of PFS and OS were determined using the Kaplan-Meier method, and differences were compared using the log-rank test. A Cox proportional-hazards model was used for multivariate analysis. The χ 2 test or Mann-Whitney test was applied to assess differences between variables. The interobserver agreement for FISH was assessed using the κ statistic; a κ value of &gt;0.75 implied excellent agreement. All statistical calculations, except for ROC and the κ statistic which were performed with SPSS 18.0 (SPSS Inc., Chicago, IL, USA), were conducted using StatView (Abacus Concepts, Berkeley, CA, USA). Results Patients&apos; characteristics and outcome The median age of the patients at diagnosis was 62 years (range, 18-86). Their clinical characteristics are reported in BCL2 and MYC genes in the subgroups defined by gene expression profiling Sixty patients (18.3%) had DLBCL with BCL2 gene translocations, and 50 (15.3%) had BCL2 gene amplifications. The presence of BCL2 translocations was not associated with any clinical prognostic variable at diagnosis, except for Ann Arbor Stage (70% versus 49% with stage III-IV, P=0.004), as shown in The OS and PFS rates of patients with BCL2 translocations were similar to those of patients without BCL2 translocations, irrespectively of MYC status. When we restricted the analysis to the GCB subtype, patients with BCL2 translocations alone, in the absence of MYC breaks, had a significantly worse outcome than GCB patients without BCL2 translocations (3-year PFS of 53% versus 76%, respectively; P=0.0002). The outcome of patients with BCL2 rearranged GCB subtype was similar to that of the patients with the ABC subtype of DLBCL (52%, P=0.30), but still better than that of the patients with double hit lymphomas (P&lt;0.0001, The presence of MYC breaks alone in the 19 patients without concomitant BCL2 translocations was not associated with impaired PFS (P=0.70) or OS (P=0.66) in the whole cohort, but was associated with inferior OS (P=0.03), but not PFS (P=0.22), in patients with GCB-DLBCL (only 9 with isolated MYC breaks). As shown in BCL2 gains were not prognostic in any of the subgroups of patients. Particular consideration of high-level amplifications was of no additional prognostic value. Bcl-2 protein expression, clinical characteristics, fluorescence in situ hybridization and gene expression profiling None of the common clinical characteristics of our patients at the time of presentation was significantly associated with Bcl-2 protein expression except age, with older patients more often being Bcl-2 positive (≥60 years old, P=0.02). Bcl-2 protein expression in GEP-and FISHdefined subgroups is shown in © F e r r a t a S t o r t i F o u n d a t i o n patients without the BCL2 translocation (range, 0-100%; median 60%). Bcl-2 protein expression was significantly associated with worse PFS (P=0.01) and OS (P=0.02) in the whole cohort, but when patients were divided according to GEPdefined subtypes, we observed that higher Bcl-2 expression was associated with significantly inferior PFS in the GCB subgroup (P=0.04), but not in the ABC subgroup (P=0.57), as shown in Multivariate analysis Multivariate analysis of all 137 patients with the GCB subtype of DLBCL showed that BCL2 translocations (HR 0.40, 95% CI: 0.18-0.89; P=0.02), but not Bcl-2 expression (HR 1.01, 95% CI: 0.45-2.21; P=0.98), MYC breaks (HR 0.25, 95% CI: 0.10-0.59; P=0.001), and IPI score (HR 0.41, 95% CI: 0.20-0.84; P=0.01), were independently associated with patients&apos; outcome. Results were not modified after each molecular feature was computed with age as a continuous parameter. C. Visco et al. 258 haematologica | 2013; 98(2) Overall survival Progression-free survival Four-hundred and forty-four genes were found to be differentially expressed (&gt;1.5 fold and P&lt;0.005) in DLBCL patients with or without BCL2 translocations including both GCB and ABC subtypes. In the GCB group, however, only 43 genes were differentially expressed among patients with and without BCL2 translocations ( Interestingly, a number of genes overexpressed in the BCL2 translocated group are involved in the control of angiogenesis and the inflammatory response (AIMP1, PPIA, and ALOX), while others are involved in promoting apoptosis or regulating B-cell signaling (STK17A, RAL-GPS2, NCOA3, STRBP, and ZNF117). 35-37 C. Visco et al. 260 haematologica | 2013; 98(2) © F e r r a t a S t o r t i F o u n d a t i o n Discussion We addressed the clinical impact of BCL2 aberrations and their relationship to Bcl-2 protein expression in a large series of patients with DLBCL homogeneously treated with R-CHOP, with known MYC gene status and molecularly characterized according to GEP analysis. We were able to establish the role of the BCL2 gene in different subtypes of DLBCL, irrespectively of concomitant MYC aberrations. We found that isolated BCL2 translocations, in the absence of MYC breaks, were associated with a poor outcome in the subset of patients with GCB-DLBCL, and that the prognosis of these patients was similar to that of patients with ABC-DLBCL. The concomitant presence of MYC breaks (double hit lymphoma) further worsened the outcome of these patients. The role of Bcl-2 protein expression appeared dependent on its association with BCL2 translocations, as outlined by multivariate analysis and survival curves As determined by FISH break apart probe analysis, the overall frequency of BCL2 translocations in de novo DLBCL was 18.3%. The BCL2 translocations were almost exclusively associated with GCB-DLBCL, found in 34.5% of cases The impact of BCL2 translocations on survival in our series could not be explained by differences in the clinical features of the patients because there was no association between the presence of BCL2 translocations and IPI risk groups (P=0.90, A C B FIGURE A COLORI SOLO ONLINE © F e r r a t a S t o r t i F o u n d a t i o n with isolated BCL2 or MYC lesions. Confirming previous findings, In this series, Bcl-2 protein was overexpressed in half of the patients with GCB-DLBCL and in 72% of patients with ABC-DLBCL 18,39 However, Bcl-2 overexpression had prognostic value only in the GCB subtype, as already observed by others in the era of R-CHOP therapy. Iqbal et al. 22 Secondly, Bcl-2 protein expression in Iqbal&apos;s study was significantly associated with adverse clinical prognostic factors (stage III-IV, elevated lactate dehydrogenase, high IPI risk group) in GCB-DLBCL, which was not the case in our study. Finally, no mention was made about exclusion of possibly confounding DLBCL subtypes such as double hit lymphoma, primary cutaneous or primary central nervous system DLBCL. We also acknowledge that different findings in the literature regarding BCL2 rearrangements or protein expression could very well be related to lack of uniformity between different studies in terms of Bcl-2 staining and scoring. Moreover, patients&apos; characteristics in the different series, differences in the management of the cases as they were not in clinical trials, data collection regarding outcome, and sometimes short follow-up times may also have contributed to different results. Our GEP analysis revealed that patients with BCL2 translocations substantially differed with respect to important recurrent oncogenic events, which may contribute to the adverse outcome of the subgroup of GCB-DLBCL patients with BCL2 translocations. Up-regulation of the BCL11A gene occurred exclusively in the group of patients with BCL2 translocations We confirm that the outcome of GCB-DLBCL patients should be interpreted in the context of abnormalities of the MYC and BCL2 genes. While the MYC rearrangement is quite rare, it is rarely found as the sole genetic abnormality, and its clinical relevance is mainly related to a double hit mechanism, BCL2 rearrangements are present in a considerable fraction of patients with the GCB subtype who have similar outcomes to those of patients with the ABC subtype. Our results confirm that the GCB and ABC subtypes of DLBCL have distinct pathogeneses, and support the rationale for further classification of different subgroups. © F e r r a t a S t o r t i F o u n d a t i o n Funding CV is a hematologist supported by Sa

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Lentiviral vectors for immune cells targeting

Lentiviral vectors are efficient gene delivery vehicles suitable for delivering long-term transgene expression in various cell types. Engineering lentiviral vectors to have the capacity to transduce specific cell types is of great interest to advance the translation of lentiviral vectors towards the clinic. Here we provide an overview of innovative approaches to target lentiviral vectors to cells of the immune system. In this overview we distinguish between two types of lentiviral vector targeting strategies: 1) targeting of the vectors to specific cells by lentiviral vector surface modifications, and 2) targeting at the level of transgene transcription by insertion of tissue-specific promoters to drive transgene expression. It is clear that each strategy is of enormous value but ultimately combining these approaches may help reduce the effects of off-target expression and improve the efficiency and saftey of lentiviral vectors for gene therapy