Biology subjects

Sugata, K.

Publications and source records attributed to Sugata, K..

4 recordsLinked to original sources

bioRxiv2024

Viral antigen mismatch affects antiviral T-cell response and may impair immunotherapeutic efficacy against ATL

Human T-cell leukemia virus type 1 (HTLV-1) has the potential to transform primary CD4+ T cells in vitro within a short time; however, the majority of infected individuals maintain an asymptomatic and disease-free condition, suggesting the existence of an equilibrium between the proliferation of infected cells and host immunity. The decline in anti-viral immunity contributes to the transformation of the infected cells, leading to the development of adult T-cell leukemia/lymphoma (ATL). This study identified a variation in a major viral antigen, HTLV-1 Tax, in human leukocyte antigen-A24 (HLA-A24) positive individuals. Two variants of Tax301-309 peptides, SFHNLHLLF (Tax301-309 A) and SFHSLHLLF (Tax301-309 B) were found to induce distinct T-cell immune responses in HLA-A24 positive individuals. There was a disparity between two Tax301-309 peptides in the detection of anti-Tax301-309 cytotoxic T-lymphocytes (CTLs) binding to A24/peptide multimers by flow cytometry analysis. More importantly, over half of the anti-Tax TCRs of anti-Tax CTLs from infected individuals did not recognize mismatched Tax301-309 peptides by Enzyme-Linked Immunospot (ELISpot) assay using Jurkat T cells expressing the anti-Tax301-309 specific TCR. These findings underscore the importance of matching the viral antigen epitope type in T-cell-based immunotherapy against ATL by using viral antigen Tax. Key pointsO_LIEpitope heterogeneity in the major viral antigen in HTLV-1 infection causes different T-cell responses in infected individuals. C_LIO_LIRecommended guideline; performing virus typing to obtain optimal efficacy in T-cell-mediated immunotherapy against the viral antigen Tax C_LI

immunology↗

bioRxiv2023

HIV-Tocky system to visualize proviral expression dynamics

The stably integrated pool of HIV-1 proviruses in the host genome stands against curative strategies. This reservoir is extremely heterogeneous with respect to host cell type, anatomical location, integration site, and replication fitness. During the initial phase of infection, only a few infected cells can resist host immune clearance or cytopathic effect and establish this resistant pool. The mechanisms underlying HIV latency initiation are not fully resolved yet. In the current study, we propose and validate a new reporter model for monitoring HIV-1 provirus silencing and reactivation using Timer of cell kinetics and activity (Tocky). HIV-Tocky system uses a fluorescent Timer protein whose emission spectrum spontaneously shifts from blue to red to reveal HIV-1 provirus dynamics. We dissected provirus transcriptional phases into early, persistent, recently silenced, and latent. To our knowledge, this is the first report to distinguish two latent subsets: a directly non-expressing population and a recently silenced after brief expression. In-depth integration site analysis suggested that the distribution of proviruses in directly latent cells was similar to that in actively transcribing cell population, whereas recently silenced cells tended to harbor proviruses integrated into heterochromatin. Furthermore, we established a library of various single integration clones at which we utilized to demonstrate the efficiency of the block-and-lock strategy by capturing the fast dynamics of silencing that were overlooked in previous models. In summary, we propose HIV-Tocky system to serve as a time-sensitive model that can capture the dynamics of provirus expression, making it a useful tool for HIV latency research. Significance StatementDeterminants of HIV-1 latency establishment are yet to be elucidated. This reservoir comprises a rare fraction of infected cells that can survive host and virus-mediated killing. In vitro reporter models so far offered a feasible means to inspect this population, but with limited capabilities to dissect provirus silencing dynamics. Here, we describe a new HIV reporter model (HIV-Tocky) with dual fluorescence spontaneous shifting to reveal provirus silencing and reactivation dynamics. This unique feature allowed; for the first time, identifying two latent populations: a directly latent, and a recently silenced subset, with the latter having integration features suggestive of stable latency. Our proposed model can help address the heterogeneous nature of HIV reservoirs and offers new possibilities for evaluating eradication strategies. ClassificationBiological Sciences, Microbiology.

microbiology↗

bioRxiv2022

Lymphoma cells are circulating in blood of Enzootic Bovine Leukosis and clonality value of virus-infected cells is a useful information for the diagnostic test

Bovine leukemia virus (BLV), a retrovirus, causes Enzootic Bovine Leukosis (EBL) in cattle following a latent infection period. The BLV infection results in polyclonal expansion of infected B-lymphocytes and [~]5% of infected cattle develop monoclonal leukosis. Since the clonal expansion of virus-infected cell is a key in the pathogenesis of EBL, assessing the clonality of malignant cells is crucial for both understanding viral pathogenesis, which might be useful for EBL diagnosis. For the investigation of clonality of BLV-infected cells in non-EBL and EBL cattle, two methods were used to evaluate the status of EBL; BLV-DNA-capture-seq method with high sensitivity and specificity and simple and cost-effective Rapid Amplification of Integration Site for BLV (BLV-RAIS) method. We found that the RAIS method efficiently detect expanded clone in EBL tissue sample as BLV-DNA-capture-seq method. Taking advantage of high frequency of BLV-infected cells in blood, we simplified RAIS method and showed that similar to BLV-DNA-capture-seq, this method could reliably provide quantitative value about clonal abundance of BLV-infected cells. Next, we aimed to establish a diagnostic blood test for EBL by using the clonality information. First, we compared clonality of BLV-infected cells in blood with that in tumor tissue in EBL cattle. There was a remarkably similar clonality between blood and tissue in each animal. Furthermore, BLV integration site information clearly showed that the same clone was the most expanded in both blood and tumor tissue, indicating that tumor cells were circulating in blood in the disease cattle. We also analyzed tumor tissue at two independent anatomical regions and found the same clones was most expanded in both regions, supporting the idea that tumor cells are systemically circulating in the diseased cattle. Finally, we compared clonality value between non-EBL and EBL cattle by using BLV-RAIS method and found that there was clear difference between non-EBL and EBL. More importantly, we found that clonality value was low in asymptomatic phase but high in EBL phase in the longitudinal cohort study. These findings have demonstrated that BLV integration site and clonality value are is a useful information to establish diagnostic blood test for EBL. That would contribute to reduction of economic damage caused by EBL and improvement of productivity in cattle industry.

zoology↗

bioRxiv2021

Retrovirus-induced leukemia - hijack of T-cell activation mechanisms revealed by single-cell analysis

Human T-cell leukemia virus type 1 (HTLV-1) mainly infects CD4+ T-cells and induces chronic, persistent infection in infected individuals with some progressing to develop adult T-cell leukemia/lymphoma (ATL). Whilst HTLV-1 alters cellular differentiation, activation and survival, it is unknown whether and how these changes contribute to malignant transformation of infected T-cells. In this study, we used single-cell RNA-Seq and TCR-Seq to investigate T-cell differentiation and HTLV-1-mediated transformation processes. We analyzed 87,742 single cells from peripheral blood of 12 infected and 3 uninfected individuals. Using multiple independent bioinformatic methods, we demonstrated that naive T-cells dynamically change into activated T-cells including infected cells, which seamlessly transitioned into ATL cells characterized by clonally expanded, highly-activated T-cells. Notably, the more activated ATL cells are, the more they acquire Treg signatures. Intriguingly, HLA class II genes were uniquely induced in infected cells, further upregulated in ATL cells and was induced by viral protein Tax. Functional assays revealed that by upregulating HLA class II, HTLV-1-infected cells can act as tolerogenic antigen presenting cells (APCs) to induce anergy of antigen specific T-cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1-mediated transformation and immune escape at single-cell level. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/458291v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@38d0fdorg.highwire.dtl.DTLVardef@20cca0org.highwire.dtl.DTLVardef@15a55e2org.highwire.dtl.DTLVardef@1bca6ac_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗