Establishment of a novel human T-cell leukemia virus type 1 infection model using cell-free virus.

The primary mode of infection by human T-cell leukemia virus type 1 (HTLV-1) is cell-to-cell transmission during contact between infected cells and target cells. Cell-free HTLV-1 infections are known to be less efficient than infections with other retroviruses, and transmission of free HTLV-1 is considered not to occur in vivo. However, it has been demonstrated that cell-free HTLV-1 virions can infect primary lymphocytes and dendritic cells in vitro, and that virions embedded in biofilms on cell membranes can contribute to transmission. The establishment of an efficient cell-free HTLV-1 infection model would be a useful tool for analyzing the replication process of HTLV-1 and the clonal expansion of infected cells. We first succeeded in obtaining supernatants with high-titer cell-free HTLV-1 using a highly efficient virus-producing cell line. The HTLV-1 virions retained the structural characteristics of retroviruses. Using this cell-free infection model, we confirmed that a variety of cell lines and primary cultured cells can be infected with HTLV-1 and demonstrated that the provirus was randomly integrated into all chromosomes in the target cells. The provirus-integrated cell lines were HTLV-1-productive. Furthermore, we demonstrated for the first time that cell-free HTLV-1 is infectious in vivo using a humanized mouse model. These results indicate that this cell-free infection model recapitulates the HTLV-1 life cycle, including entry, reverse transcription, integration into the host genome, viral replication, and secondary infection. The new cell-free HTLV-1 infection model is promising as a practical resource for studying HTLV-1 infection.IMPORTANCECo-culture of infected and target cells is frequently used for studying HTLV-1 infection. Although this method efficiently infects HTLV-1, the cell mixture is complex, and it is extremely difficult to distinguish donor infected cells from target cells. In contrast, cell-free HTLV-1 infection models allow for more strict experimental conditions. In this study, we established a novel and efficient cell-free HTLV-1 infection model. Using this model, we successfully evaluated the infectivity titers of cell-free HTLV-1 as proviral loads (copies per 100 cells) in various cell lines, primary cultured cells, and a humanized mouse model. Interestingly, the HTLV-1-associated viral biofilms played an important role in enhancing the infectivity of the cell-free infection model. This cell-free HTLV-1 infection model reproduces the replication cycle of HTLV-1 and provides a simple, powerful, and alternative tool for researching HTLV-1 infection.

Performance evaluation of Espline HTLV-I/II, a newly developed rapid immunochromatographic antibody test for different diagnostic situations.

IMPORTANCE: The World Health Organization estimated that 5-10 million people are infected with human T-cell leukemia virus type 1 (HTLV-1). This number is likely to be underestimated because reliable endemic data are available for only approximately 1.5 billion people worldwide. The point-of-care test is a powerful tool for the easy and quick detection of infections without the requirement for expensive instruments and laboratory equipment. Espline HTLV-I/II, a newly developed rapid immunochromatographic antibody test that was evaluated in this study, might significantly advance our understanding of the global epidemiology of HTLV-1 infection.

Efficacy of convalescent plasma therapy for COVID-19 in Japan: An open-label, randomized, controlled trial.

BACKGROUND: Convalescent plasma is a potential therapeutic option for patients with coronavirus disease 2019 (COVID-19). Despite its use for treating several viral infections, we lack comprehensive data on its efficacy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We conducted a multicenter, open-label, randomized controlled trial of convalescent plasma therapy with high neutralizing activity against SARS-CoV-2 in high-risk patients within five days after the onset of COVID-19 symptoms. The primary endpoint was the time-weighted average change in the SARS-CoV-2 viral load in nasopharyngeal swabs from days 0-5. RESULTS: Between February 24, 2021, and November 30, 2021, 25 patients were randomly assigned to either convalescent plasma (n = 14) or standard of care (n = 11) groups. Four patients discontinued their allocated convalescent plasma, and 21 were included in the modified intention-to-treat analysis. The median interval between the symptom onset and plasma administration was 4.5 days (interquartile range, 3-5 days). The primary outcome of the time-weighted average change in the SARS-CoV-2 viral load in nasopharyngeal swabs did not significantly differ between days 0-5 (1.2 log10 copies/mL in the convalescent plasma vs. 1.2 log10 copies/mL in the standard of care (effect estimate, 0.0 [95% confidence interval, -0.8-0.7]; P = 0.94)). No deaths were observed in either group. CONCLUSIONS: The early administration of convalescent plasma with high neutralizing activity did not contribute to a decrease in the viral load within five days compared with the standard of care alone.

pH-Responsive Lipid Nanoparticles Achieve Efficient mRNA Transfection in Brain Capillary Endothelial Cells.

The blood-brain barrier (BBB), which is comprised of brain capillary endothelial cells, plays a pivotal role in the transport of drugs from the blood to the brain. Therefore, an analysis of proteins in the endothelial cells, such as transporters and tight junction proteins, which contribute to BBB function, is important for the development of therapeutics for the treatment of brain diseases. However, gene transfection into the vascular endothelial cells of the BBB is fraught with difficulties, even in vitro. We report herein on the development of lipid nanoparticles (LNPs), in which mRNA is encapsulated in a nano-sized capsule composed of a pH-activated and reductive environment-responsive lipid-like material (ssPalm). We evaluated the efficiency of mRNA delivery into non-polarized human brain capillary endothelial cells, hCMEC/D3 cells. The ssPalm LNPs permitted marker genes (GFP) to be transferred into nearly 100% of the cells, with low toxicity in higher concentration. A proteomic analysis indicated that the ssPalm-LNP had less effect on global cell signaling pathways than a Lipofectamine MessengerMAX/GFP-encoding mRNA complex (LFN), a commercially available transfection reagent, even at higher mRNA concentrations.

Upregulation of ribosome complexes at the blood-brain barrier in Alzheimer's disease patients.

The cerebrovascular-specific molecular mechanism in Alzheimer's disease (AD) was investigated by employing comprehensive and accurate quantitative proteomics. Highly purified brain capillaries were isolated from cerebral gray and white matter of four AD and three control donors, and examined by SWATH (sequential window acquisition of all theoretical fragment ion spectra) proteomics. Of the 29 ribosomal proteins that were quantified, 28 (RPLP0, RPL4, RPL6, RPL7A, RPL8, RPL10A, RPL11, RPL12, RPL14, RPL15, RPL18, RPL23, RPL27, RPL27A, RPL31, RPL35A, RPS2, RPS3, RPS3A, RPS4X, RPS7, RPS8, RPS14, RPS16, RPS20, RPS24, RPS25, and RPSA) were significantly upregulated in AD patients. This upregulation of ribosomal protein expression occurred only in brain capillaries and not in brain parenchyma. The protein expression of protein processing and N-glycosylation-related proteins in the endoplasmic reticulum (DDOST, STT3A, MOGS, GANAB, RPN1, RPN2, SEC61B, UGGT1, LMAN2, and SSR4) were also upregulated in AD brain capillaries and was correlated with the expression of ribosomal proteins. The findings reported herein indicate that the ribosome complex, the subsequent protein processing and N-glycosylation-related processes are significantly and specifically upregulated in the brain capillaries of AD patients.

Regional Differences in the Absolute Abundance of Transporters, Receptors and Tight Junction Molecules at the Blood-Arachnoid Barrier and Blood-Spinal Cord Barrier among Cervical, Thoracic and Lumbar Spines in Dogs.

PURPOSE: The purpose of the present study was to quantitatively determine the expression of transporters, receptors and tight junction molecules at the blood-arachnoid barrier (BAB) and blood-spinal cord barrier (BSCB) in cervical, thoracic and lumbar spines from dogs. METHODS: The expression levels of 31 transporters, 3 receptors, 1 tight junction protein, and 3 marker proteins in leptomeninges and capillaries isolated from spines (3 male and 2 female dogs) were determined by quantitative Targeted Absolute Proteomics (qTAP). The units were converted from fmol/µg protein to pmol/cm (absolute abundance at the BAB and the BSCB in a 1 cm section of spine). RESULTS: The expression of MDR1 and BCRP were greater at the BSCB compared to the BAB (especially in the cervical cord), and the expressions at the lumbar BSCB were lower than that for the cervical BSCB. Among the organic anionic and cationic drug transporters, OAT1, OAT3, MRP1, OCT2 and MATE1/2 were detected only in the BAB, and not at the BSCB). The expression of these transporters was higher in the order: lumbar > thoracic > cervical BAB. The expressions of GLUT1, 4F2hc, EAAT1, 2, PEPT2, CTL1, and MCT1 at the BSCB of the cervical cord were higher than the corresponding values for the cervical BAB, and these values decreased in going down the spinal cord. CONCLUSION: These results provide a better understanding of the molecular mechanisms underlying the concentration gradients of drugs and endogenous substances in the cerebrospinal fluid and parenchyma of the spinal cord.

Cytolytic Recombinant Vesicular Stomatitis Viruses Expressing STLV-1 Receptor Specifically Eliminate STLV-1 Env-Expressing Cells in an HTLV-1 Surrogate Model In Vitro.

Human T-cell leukemia virus type 1 (HTLV-1) causes serious and intractable diseases in some carriers after infection. The elimination of infected cells is considered important to prevent this onset, but there are currently no means by which to accomplish this. We previously developed "virotherapy", a therapeutic method that targets and kills HTLV-1-infected cells using a cytolytic recombinant vesicular stomatitis virus (rVSV). Infection with rVSV expressing an HTLV-1 primary receptor elicits therapeutic effects on HTLV-1-infected envelope protein (Env)-expressing cells in vitro and in vivo. Simian T-cell leukemia virus type 1 (STLV-1) is closely related genetically to HTLV-1, and STLV-1-infected Japanese macaques (JMs) are considered a useful HTLV-1 surrogate, non-human primate model in vivo. Here, we performed an in vitro drug evaluation of rVSVs against STLV-1 as a preclinical study. We generated novel rVSVs encoding the STLV-1 primary receptor, simian glucose transporter 1 (JM GLUT1), with or without an AcGFP reporter gene. Our data demonstrate that these rVSVs specifically and efficiently infected/eliminated the STLV-1 Env-expressing cells in vitro. These results indicate that rVSVs carrying the STLV-1 receptor could be an excellent candidate for unique anti-STLV-1 virotherapy; therefore, such antivirals can now be applied to STLV-1-infected JMs to determine their therapeutic usefulness in vivo.

Activation of Annexin A2 signaling at the blood-brain barrier in a mouse model of multiple sclerosis.

Blood-brain barrier (BBB) dysfunction is a fundamental cause of multiple sclerosis and identifying the molecules that are responsible is an urgent matter. Protein expression was comprehensively quantified at the BBB of experimental autoimmune encephalomyelitis (EAE) mice, a model of multiple sclerosis, using the SWATH method. Concerning tight junction molecules, the level of expression of Claudin-5, which, in a previous immunohistochemical analysis, was confirmed to be down-regulated by EAE, remained unchanged, but the expression of Claudin-11 and Occludin was decreased by 0.69- and 0.62-fold, respectively, in brain capillaries isolated from EAE mice. A number of other cell-cell junctional molecules including ESAM, CADM1, CADM2, CADM3, CADM4, and HEPACAM were also down-regulated. The levels of expression of intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1), which directly mediate the infiltration of lymphocytes across the BBB, were increased in EAE mice by 3.3- and 2.6-fold, respectively. The expression of CXADR, which possibly facilitates the adhesion of migrating cells, was also increased by 3.5-fold. Interestingly, various members of the Annexin A (ANXA) family were also up-regulated in brain capillaries that were isolated from EAE mice. In a pathway associated with cell infiltration and tight junction disruption, a series of molecules that are involved in ANXA2 signaling (ANXA2, PTP1B, Ahnak, S100A11, CD44, Kindlin2, Integrin α5, Fibronectin, Fibrinogen) were up-regulated. ANXA2 is selectively and abundantly expressed in endothelial cells in the brain. The daily administration of an ANXA2 inhibitor (LCKLSL peptide) significantly suppressed the development of EAE in mice. In summary, the activation of ANXA2 signaling at the BBB appear to play an important role in the pathogenesis of EAE.

How we secured a COVID-19 convalescent plasma procurement scheme in Japan.

BACKGROUND: In order to tackle the COVID-19 pandemic, a COVID-19 convalescent plasma (CCP) procurement program was initiated in Japan in April 2020. The program was a collaboration between a government-managed national hospital, an infectious disease research institute, and a blood banking organization. Each party assumed different responsibilities: recruitment, SARS-CoV-2 antibody profiling, and plasmapheresis; conduction of screening tests; and SARS-CoV-2 blood testing, respectively. METHODS: We adopted a two-point screening approach before the collected CCP was labeled as a CCP product for investigational use, for which we mainly tested anti-SARS-CoV-2 antibody eligibility and blood product eligibility. Anti-SARS-CoV-2 spike protein titer was measured using enzyme-linked immunosorbent assay, and the IC50 value was denoted as the neutralizing activity. Blood donor eligibility was extended beyond the normal blood donation guidelines to include a broader range of participants. After both eligibility criteria were confirmed, participants were asked to revisit the hospital for blood donation, which is a unique aspect of the Japanese CCP program, as most donations are taking place in normal blood donation venues in other countries. Some donors were re-scheduled for repeat plasma donations. As public interest in anti-SARS-CoV-2 antibodies increased, test results were given to the participants. RESULTS: As of September 17, 2020, our collection of CCP products was sufficient to treat more than 100 patients. As a result, projects for administration and distribution are also being conducted. CONCLUSIONS: We successfully implemented a CCP procurement scheme with the goal to expand to other parts of the country to improve treatment options for COVID-19.

No SARS-CoV-2 RNA detected in the convalescent plasma of COVID-19 patients with different disease severity.

INTRODUCTION: Convalescent plasma transfusion (CPT), a potential therapy for coronavirus disease 2019 (COVID-19), requires strict quality control of the donor blood. Whether to confirm the disappearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (RNAemia) in convalescent donor blood or not is unclear. Reports recommending the proof of viral disappearance from the blood are controversial. Foreseeing CPT in treating COVID-19 patients in Japan, we investigated RNAemia in 100 convalescent donors with mild, moderate, and severe COVID-19. METHODS: Between April 30 and July 30, 2020, we measured RNAemia in the plasma samples of donors with resolved COVID-19. Data on patients' demographics, comorbidities, pneumonia, treatment, and real-time polymerase chain reaction results for SARS-CoV-2 were collected. Date of onset of initial symptoms or date of positive testing (for asymptomatic patients) were self-reported by the patients. Disease severity was defined as: no, mild, moderate oxygen demand, or severe (requiring mechanical ventilation). RESULTS: Of 100 donors (58 males [58.0%]; median age, 47 [range 22-69] years) screened as of July 30, 2020, 77 (77.0%); 19 (19.0%); and 4 (4.0%) had mild, moderate, and severe disease, respectively. Median time between onset and testing was 68.5 (range, 21-167) days. SARS-CoV-2 RNA was not detected in any of the plasma samples. CONCLUSION: RNAemia was not found in recovered COVID-19 patients at least 21, 27, and 57 days after the onset of mild, moderate, and severe symptoms. Our study may contribute to determining a suitable time for collecting convalescent plasma from COVID-19 patients and to future CPT use.

HTLV-1 targets human placental trophoblasts in seropositive pregnant women.

Human T cell leukemia virus type 1 (HTLV-1) is mainly transmitted vertically through breast milk. The rate of mother-to-child transmission (MTCT) through formula feeding, although significantly lower than through breastfeeding, is approximately 2.4%-3.6%, suggesting the possibility of alternative transmission routes. MTCT of HTLV-1 might occur through the uterus, birth canal, or placental tissues; the latter is known as transplacental transmission. Here, we found that HTLV-1 proviral DNA was present in the placental villous tissues of the fetuses of nearly half of pregnant carriers and in a small number of cord blood samples. An RNA ISH assay showed that HTLV-1-expressing cells were present in nearly all subjects with HTLV-1-positive placental villous tissues, and their frequency was significantly higher in subjects with HTLV-1-positive cord blood samples. Furthermore, placental villous trophoblasts expressed HTLV-1 receptors and showed increased susceptibility to HTLV-1 infection. In addition, HTLV-1-infected trophoblasts expressed high levels of viral antigens and promoted the de novo infection of target T cells in a humanized mouse model. In summary, during pregnancy of HTLV-1 carriers, HTLV-1 was highly expressed in placental villous tissues, and villous trophoblasts showed high HTLV-1 sensitivity, suggesting that MTCT of HTLV-1 occurs through the placenta.

Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan.

BACKGROUND: The reliable diagnosis of human T-cell leukemia virus type 1 (HTLV-1) infection is important, particularly as it can be vertically transmitted by breast feeding mothers to their infants. However, current diagnosis in Japan requires a confirmatory western blot (WB) test after screening/primary testing for HTLV-1 antibodies, but this test often gives indeterminate results. Thus, this collaborative study evaluated the reliability of diagnostic assays for HTLV-1 infection, including a WB-based one, along with line immunoassay (LIA) as an alternative to WB for confirmatory testing. RESULTS: Using peripheral blood samples from blood donors and pregnant women previously serologically screened and subjected to WB analysis, we analyzed the performances of 10 HTLV-1 antibody assay kits commercially available in Japan. No marked differences in the performances of eight of the screening kits were apparent. However, LIA determined most of the WB-indeterminate samples to be conclusively positive or negative (an 88.0% detection rate). When we also compared the sensitivity to HTLV-1 envelope gp21 with that of other antigens by LIA, the sensitivity to gp21 was the strongest. When we also compared the sensitivity to envelope gp46 by LIA with that of WB, LIA showed stronger sensitivity to gp46 than WB did. These findings indicate that LIA is an alternative confirmatory test to WB analysis without gp21. Therefore, we established a novel diagnostic test algorithm for HTLV-1 infection in Japan, including both the performance of a confirmatory test where LIA replaced WB on primary test-reactive samples and an additional decision based on a standardized nucleic acid detection step (polymerase chain reaction, PCR) on the confirmatory test-indeterminate samples. The final assessment of the clinical usefulness of this algorithm involved performing WB analysis, LIA, and/or PCR in parallel for confirmatory testing of known reactive samples serologically screened at clinical laboratories. Consequently, LIA followed by PCR (LIA/PCR), but neither WB/PCR nor PCR/LIA, was found to be the most reliable diagnostic algorithm. CONCLUSIONS: Because the above results show that our novel algorithm is clinically useful, we propose that it is recommended for solving the aforementioned WB-associated reliability issues and for providing a more rapid and precise diagnosis of HTLV-1 infection.

Activation of PERK-ATF4-CHOP pathway as a novel therapeutic approach for efficient elimination of HTLV-1-infected cells.

Patients with adult T-cell leukemia (ATL) exhibit a poor prognosis and overall survival rate when treated with standard chemotherapy, highlighting the continued requirement for the development of novel safe and effective therapies for human T-cell leukemia virus type 1 (HTLV-1)-related diseases. In this study, we demonstrated that MK-2048, a second-generation HIV-1 integrase (IN) inhibitor, potently and selectively kills HTLV-1-infected cells. Differential transcriptome profiling revealed significantly elevated levels of gene expression of the unfolded protein response (UPR) PKR-like ER kinase (PERK) signaling pathway in ATL cell lines following MK-2048 treatment. We also identified a significant downregulation in glucose regulated protein 78 (GRP78), a master regulator of the UPR in the CD4+CADM1+ HTLV-1-infected cell population of primary HTLV-1 carrier peripheral blood mononuclear cells (PBMCs) (n = 9), suggesting that HTLV-1-infected cells are hypersensitive to endoplasmic reticulum (ER) stress-mediated apoptosis. MK-2048 efficiently reduced proviral loads in primary HTLV-1 carrier PBMCs (n = 4), but had no effect on the total numbers of these cells, indicating that MK-2048 does not affect the proliferation of HTLV-1-uninfected PBMCs. MK-2048 specifically activated the ER stress-related proapoptotic gene, DNA damage-inducible transcript 3 protein (DDIT3), also known as C/EBP homologous protein (CHOP), in HTLV-1-infected but not uninfected cells of HTLV-1-carrier PBMCs. Our findings demonstrated that MK-2048 selectively induces HTLV-1-infected cell apoptosis via the activation of the UPR. This novel regulatory mechanism of the HIV IN inhibitor MK-2048 in HTLV-1-infected cells provides a promising prophylactic and therapeutic target for HTLV-1-related diseases including ATL.

Development and evaluation of human T-cell leukemia virus-1 and -2 multiplex quantitative PCR.

The diagnosis of human T -cell leukemia virus type 1 (HTLV-1) infection in Japan is usually performed by serological testing, but the high rate of indeterminate results from western blotting makes it difficult to assess the infection accurately. Nucleic acid tests for HTLV-1 and/or HTLV-2 are used to confirm infection with HTLV-1 and/or HTLV-2 and are also used for the follow-up of HTLV-1 related diseases. To prepare a highly sensitive method that can discern infection with HTLV-1 and HTLV-2, a multiplex quantitative polymerase chain reaction (qPCR) by large-scale primer screening was developed. Sensitivity and specificity were evaluated by serial dilution of cell lines and by testing with known clinical samples. The resulting multiplex qPCR can detect about four copies of HTLV-1 provirus per 105 cells. Moreover, HTLV-1 provirus could be detected in 97.2% (205 of 211) of HTLV-1 seropositive clinical samples. These sensitivities were sufficiently high compared with the methods reported previously. Also, all the HTLV-2 seropositive clinical samples tested were found to be positive by this method (three of three). In conclusion, this method can successfully and simultaneously detect both types of HTLV-1 and HTLV-2 provirus with extremely high sensitivity.

Development of reference material with assigned value for human T-cell leukemia virus type 1 quantitative PCR in Japan.

Quantitative PCR (qPCR) of human T-cell leukemia virus type 1 (HTLV-1) provirus is used for HTLV-1 testing and for assessment of risk of HTLV-1-related diseases. In this study, a reference material was developed for standardizing HTLV-1 qPCR. Freeze-dried TL-Om1 cells diluted with Jurkat cells were prepared and an assigned value for proviral load (PVL) of 2.71 copies/100 cells was determined by digital PCR. Nine Japanese laboratories using their own methods evaluated the PVLs of this reference material as 1.08-3.49 copies/100 cells. The maximum difference between laboratories was 3.2-fold. Correcting measured PVLs by using a formula incorporating the assigned value of this reference material should minimize such discrepancies.

Control of Human T-Cell Leukemia Virus Type 1 (HTLV-1) Infection by Eliminating Envelope Protein-Positive Cells with Recombinant Vesicular Stomatitis Viruses Encoding HTLV-1 Primary Receptor.

Human T-cell leukemia virus type 1 (HTLV-1) infection causes adult T-cell leukemia (ATL), which is frequently resistant to currently available therapies and has a very poor prognosis. To prevent the development of ATL among carriers, it is important to control HTLV-1-infected cells in infected individuals. Therefore, the establishment of novel therapies with drugs specifically targeting infected cells is urgently required. This study aimed to develop a potential therapy by generating recombinant vesicular stomatitis viruses (rVSVs) that lack an envelope glycoprotein G and instead encode an HTLV-1 receptor with human glucose transporter 1 (GLUT1), neuropilin 1 (NRP1), or heparan sulfate proteoglycans (HSPGs), including syndecan 1 (SDC1), designated VSVΔG-GL, VSVΔG-NP, or VSVΔG-SD, respectively. In an attempt to enhance the infectivity of rVSV against HTLV-1-infected cells, we also constructed rVSVs with a combination of two or three receptor genes, designated VSVΔG-GLN and VSVΔG-GLNS, respectively. The present study demonstrates VSVΔG-GL, VSVΔG-NP, VSVΔG-GLN, and VSVΔG-GLNS have tropism for HTLV-1 envelope (Env)-expressing cells. Notably, the inoculation of VSVΔG-GL or VSVΔG-NP significantly eliminated HTLV-1-infected cells under the culture conditions. Furthermore, in an HTLV-1-infected humanized mouse model, VSVΔG-NP was capable of efficiently preventing HTLV-1-induced leukocytosis in the periphery and eliminating HTLV-1-infected Env-expressing cells in the lymphoid tissues. In summary, an rVSV engineered to express HTLV-1 primary receptor, especially human NRP1, may represent a drug candidate that has potential for the development of unique virotherapy against HTLV-1 de novo infection.IMPORTANCE Although several anti-ATL therapies are currently available, ATL is still frequently resistant to therapeutic approaches, and its prognosis remains poor. Control of HTLV-1 de novo infection or expansion of HTLV-1-infected cells in the carrier holds considerable promise for the prevention of ATL development. In this study, we developed rVSVs that specifically target and kill HTLV-1 Env-expressing cells (not ATL cells, which generally do not express Env in vivo) through replacement of the G gene with HTLV-1 receptor gene(s) in the VSV genome. Notably, an rVSV engineered to express human NRP1 controlled the number of HTLV-1-infected Env-expressing cells in vitro and in vivo, suggesting the present approach may be a promising candidate for novel anti-HTLV-1 virotherapy in HTLV-1 carriers, including as a prophylactic treatment against the development of ATL.

Establishment of a reference material for standardization of the anti-complementary activity test in intravenous immunoglobulin products used in Japan: A collaborative study.

Aggregates of human plasma-derived intravenous immunoglobulins (IVIGs) carries a risk of severe adverse events after nonspecific complement activation induced in humans administrated. Therefore, the anti-complementary activity (ACA) test is legally required in every batch of IVIGs in Japan. However, due to the intrinsic nature of this bioassay, there might be large differences in the results of ACA tests from laboratories, even when the same batch of IVIGs was measured. Our six laboratories evaluated whether there were such differences and argued for establishment of a reference material (RM) for standardization of the ACA test. Our results revealed inter-laboratory differences in ACA values, indicating a need to establish an RM. Therefore, after ACA values in candidate RMs were measured collaboratively, one RM was selected from two candidates and unit value-assigned. The RM in fact normalized the ACA test values for samples measured in parallel at almost all the laboratories, when the values were calculated relative to the assigned unit value of the RM. Thus, we established a first RM to standardize the ACA test in Japan, which enabled each laboratory to normalize ACA values constantly for IVIGs. This indicates that the establishment of an RM can contribute to quality control of IVIGs.

Development of a novel dengue virus serotype-specific multiplex real-time reverse transcription-polymerase chain reaction assay for blood screening.

BACKGROUND: Dengue fever is caused by four related RNA viruses of the genus Flavivirus, dengue virus (DENV)-1, -2, -3, and -4, which are transmitted to humans by mosquitoes. Although DENV is not endemic in Japan, an autochthonous dengue outbreak occurred in 2014. Several transfusion-transmitted cases have also been reported after the use of blood and plasma products in DENV-endemic countries. The aim of this study was to develop a novel multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay for DENV blood screening. STUDY DESIGN AND METHODS: Large-scale oligonucleotide screening was performed to obtain DENV-specific primers and probes using a variety of DENV clinical isolates. A multiplex RT-PCR assay was then developed using the identified oligonucleotides and the ability of this assay to detect DENV RNA was evaluated. RESULTS: A number of oligonucleotides suitable for DENV RNA detection were identified and a novel DENV serotype-specific multiplex RT-PCR assay was successfully established. Comparative analysis revealed that the multiplex assay could detect levels of viral contamination as low as 100 viral copies/mL. CONCLUSION: This established serotype-specific multiplex RT-PCR assay provides a simple, sensitive, and quantitative detection method for DENV, which could be applied in the screening of blood samples to prevent transfusion-transmitted DENV infection.

Postischemic Anhedonia Associated with Neurodegenerative Changes in the Hippocampal Dentate Gyrus of Rats.

Poststroke depression is one of the major symptoms observed in the chronic stage of brain stroke such as cerebral ischemia. Its pathophysiological mechanisms, however, are not well understood. Using the transient right middle cerebral artery occlusion- (MCAO-, 90 min) operated rats as an ischemia model in this study, we first observed that aggravation of anhedonia spontaneously occurred especially after 20 weeks of MCAO, and it was prevented by chronic antidepressants treatment (imipramine or fluvoxamine). The anhedonia specifically associated with loss of the granular neurons in the ipsilateral side of hippocampal dentate gyrus and was also prevented by an antidepressant imipramine. Immunohistochemical analysis showed increased apoptosis inside the granular cell layer prior to and associated with the neuronal loss, and imipramine seemed to recover the survival signal rather than suppressing the death signal to prevent neurons from apoptosis. Proliferation and development of the neural stem cells were increased transiently in the subgranular zone of both ipsi- and contralateral hippocampus within one week after MCAO and then decreased and almost ceased after 6 weeks of MCAO, while chronic imipramine treatment prevented them partially. Overall, our study suggests new insights for the mechanistic correlation between poststroke depression and the delayed neurodegenerative changes in the hippocampal dentate gyrus with effective use of antidepressants on them.

An animal model of adult T-cell leukemia: humanized mice with HTLV-1-specific immunity.

Human T-cell leukemia virus type 1 (HTLV-1) is causally associated with adult T-cell leukemia (ATL), an aggressive T-cell malignancy with a poor prognosis. To elucidate ATL pathogenesis in vivo, a variety of animal models have been established; however, the mechanisms driving this disorder remain poorly understood due to deficiencies in each of these animal models. Here, we report a novel HTLV-1-infected humanized mouse model generated by intra-bone marrow injection of human CD133(+) stem cells into NOD/Shi-scid/IL-2Rγc null (NOG) mice (IBMI-huNOG mice). Upon infection, the number of CD4(+) human T cells in the periphery increased rapidly, and atypical lymphocytes with lobulated nuclei resembling ATL-specific flower cells were observed 4 to 5 months after infection. Proliferation was seen in both CD25(-) and CD25(+) CD4 T cells with identical proviral integration sites; however, a limited number of CD25(+)-infected T-cell clones eventually dominated, indicating an association between clonal selection of infected T cells and expression of CD25. Additionally, HTLV-1-specific adaptive immune responses were induced in infected mice and might be involved in the control of HTLV-1-infected cells. Thus, the HTLV-1-infected IBMI-huNOG mouse model successfully recapitulated the development of ATL and may serve as an important tool for investigating in vivo mechanisms of ATL leukemogenesis and evaluating anti-ATL drug and vaccine candidates.