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PLoS Neglected Tropical Diseases Feb 2024Although Japan is a major endemic area for human T-lymphotropic virus type 1 (HTLV-1) and the virus has been well-studied in this region, there is limited research on...
Geographic characteristics of HTLV-1 molecular subgroups and genetic substitutions in East Asia: Insights from complete genome sequencing of HTLV-1 strains isolated in Taiwan and Japan.
BACKGROUND
Although Japan is a major endemic area for human T-lymphotropic virus type 1 (HTLV-1) and the virus has been well-studied in this region, there is limited research on HTLV-1 in surrounding regions. In this study, we determined the complete genome sequences of HTLV-1 strains isolated from Taiwan and Japan and investigated the geographic characteristics of molecular subgroups and substitution mutations to understand the spread of HTLV-1 and its correlation with human migration.
METHODOLOGY/PRINCIPAL FINDINGS
The complete genome sequences of 26 HTLV-1 isolates from Taiwan were determined using next-generation sequencing and were compared with those of 211 isolates from Japan in terms of subgroup and genetic mutations. In total, 15/26 (58%) isolates from Taiwan belonged to the transcontinental subgroup and 11/26 (42%) isolates belonged to the Japanese subgroup. The transcontinental subgroup was significantly more prevalent among Taiwanese isolates than Japanese isolates (58% vs 18%, P < 0.0001). The mutation rate for the complete HTLV-1 sequence was as low as 0.2%. On examining individual base substitutions, the G-to-A mutation was predominant. Bayesian phylogenetic tree analysis estimated the time to the most recent common ancestor for the transcontinental and Japanese subgroups to be 28447 years. The transcontinental subgroups from Taiwan and Japan appeared to form clusters according to their respective regions.
CONCLUSIONS/SIGNIFICANCE
The transcontinental subgroup of HTLV-1 is predominant in Taiwan, while the Japanese subgroup is common in Japan. The difference in subgroup distribution may be attributed to the initial spread of the transcontinental subgroup in East Asia, followed by the influx of the Japanese subgroup.
Topics: Humans; Human T-lymphotropic virus 1; Japan; HTLV-I Infections; Taiwan; Phylogeny; Bayes Theorem; Sequence Analysis, DNA; Asia, Eastern; Whole Genome Sequencing
PubMed: 38315729
DOI: 10.1371/journal.pntd.0011928 -
Pharmaceuticals (Basel, Switzerland) Jun 2024With an estimated 10 million people infected, the deltaretrovirus human T-cell lymphotropic virus type 1 (HTLV-1) is the second most prevalent pathogenic retrovirus in...
With an estimated 10 million people infected, the deltaretrovirus human T-cell lymphotropic virus type 1 (HTLV-1) is the second most prevalent pathogenic retrovirus in humans after HIV-1. Like HIV-1, HTLV-1 overwhelmingly persists in a host via a reservoir of latently infected CD4 T cells. Although most patients are asymptomatic, HTLV-1-associated pathologies are often debilitating and include adult T-cell leukaemia/lymphoma (ATLL), which presents in mature adulthood and is associated with poor prognosis with short overall survival despite treatment. Curiously, the strongest indicator for the development of ATLL is the acquisition of HTLV-1 through breastfeeding. There are no therapeutic or preventative regimens for HTLV-1. However, antiretrovirals (ARVs), which target the essential retrovirus enzymes, have been developed for and transformed HIV therapy. As the architectures of retroviral enzyme active sites are highly conserved, some HIV-specific compounds are active against HTLV-1. Here, we expand on our work, which showed that integrase strand transfer inhibitors (INSTIs) and some nucleoside reverse transcriptase inhibitors (NRTIs) block HTLV-1 transmission in cell culture. Specifically, we find that dolutegravir, the INSTI currently recommended as the basis of all new combination antiretroviral therapy prescriptions, and the latest prodrug formula of the NRTI tenofovir, tenofovir alafenamide, also potently inhibit HTLV-1 infection. Our results, if replicated in a clinical setting, could see transmission rates of HTLV-1 and future caseloads of HTLV-1-associated pathologies like ATLL dramatically cut via the simple repurposing of already widely available HIV pills in HTLV-1 endemic areas. Considering our findings with the old medical saying "it is better to prevent than cure", we highly recommend the inclusion of INSTIs and tenofovir prodrugs in upcoming HTLV-1 clinical trials as potential prophylactics.
PubMed: 38931397
DOI: 10.3390/ph17060730 -
The Journal of Veterinary Medical... Feb 2024Enzootic bovine leukosis (EBL) is B-cell lymphoma in cattle caused by bovine leukemia virus (BLV) infection. The incidence of EBL has been increasing since 1998 in...
Enzootic bovine leukosis (EBL) is B-cell lymphoma in cattle caused by bovine leukemia virus (BLV) infection. The incidence of EBL has been increasing since 1998 in Japan, resulting in significant economic losses for farms. The BLV genome integrates with the host genome as provirus, leading to sustainably infection. Although most of the BLV-infected cattle are aleukemic, some cattle cause persistent lymphocytosis (PL) and subsequently develop EBL. Recent reports suggest the association between the risk for the transmission of BLV and the developing EBL and the proviral load (PVL) in BLV-infected cattle, which cannot measure readily in the field. This study aims to build a statistical model for predicting PVL of BLV-infected asymptomatic or PL cattle based on data accessible in the field. Five negative binomial regression models with different linear predictors were built and compared for the predictability of PVL. Consequently, the model with two explanatory variables (age in months and logarithm of lymphocyte count) was selected as the best model. The model can be used in the field as a cost-beneficial supporting tool to estimate the risk of transmission of BLV and developing EBL in infected cattle.
Topics: Cattle; Animals; Leukemia Virus, Bovine; Proviruses; Enzootic Bovine Leukosis; Lymphocyte Count; Models, Statistical; Cattle Diseases
PubMed: 38123328
DOI: 10.1292/jvms.23-0157 -
Genes May 2024Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma. The oncogene product Tax of HTLV-I is thought to play crucial roles...
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma. The oncogene product Tax of HTLV-I is thought to play crucial roles in leukemogenesis by promoting proliferation of the virus-infected cells through activation of growth-promoting genes. These genes code for growth factors and their receptors, cytokines, cell adhesion molecules, growth signal transducers, transcription factors and cell cycle regulators. We show here that Tax activates the gene coding for coactivator-associated arginine methyltransferase 1 (CARM1), which epigenetically enhances gene expression through methylation of histones. Tax activated the gene and increased protein expression, not only in human T-cell lines but also in normal peripheral blood lymphocytes (PHA-PBLs). Tax increased R17-methylated histone H3 on the target gene , concomitant with increased expression of CARM1. Short hairpin RNA (shRNA)-mediated knockdown of CARM1 decreased Tax-mediated induction of and gene expression, reduced E2F activation and inhibited cell cycle progression. Tax acted via response elements in intron 1 of the gene, through the NF-κB pathway. These results suggest that Tax-mediated activation of the gene contributes to leukemogenic target-gene expression and cell cycle progression, identifying the first epigenetic target gene for Tax-mediated trans-activation in cell growth promotion.
Topics: Humans; Protein-Arginine N-Methyltransferases; Gene Products, tax; Human T-lymphotropic virus 1; Cyclin D2; Transcriptional Activation; Interleukin-2 Receptor alpha Subunit; NF-kappa B; Histones; Epigenesis, Genetic; Jurkat Cells
PubMed: 38927636
DOI: 10.3390/genes15060698 -
Euro Surveillance : Bulletin Europeen... May 2024BackgroundHuman T-cell lymphotropic virus type 1 (HTLV-1) is a neglected virus that can cause severe disease and be transmitted from mother to child through...
BackgroundHuman T-cell lymphotropic virus type 1 (HTLV-1) is a neglected virus that can cause severe disease and be transmitted from mother to child through breastfeeding. Avoidance of breastfeeding prevents 80% of vertical transmission. The United Kingdom (UK) is currently assessing whether HTLV-1-targeted antenatal screening should be implemented.AimWe aimed to assess the impact and cost-effectiveness of a targeted programme to prevent HTLV-1 vertical transmission in England and Wales.MethodsWe estimated the number of pregnant women who have high risk of HTLV-1 infection based on their or their partner's country of birth. With data from 2021, we used a mathematical model to assess cost-effectiveness of HTLV-1 antenatal screening. We also estimated the annual number of infant infections and the number that could be prevented with screening and intervention.ResultsWe estimate that ca 99,000 pregnant women in England and Wales have high risk of HTLV-1 infection. In the absence of screening, 74 (range: 25-211) HTLV-1 infections in infants would be expected to occur every year in England and Wales. Implementation of targeted screening would prevent 58 (range: 19-164) infant infections annually. The intervention is effective (incremental 0.00333 quality-adjusted life years (QALY)) and cost-saving (GBP -57.56 (EUR -66.85)).ConclusionOur findings support implementation of HTLV-1 targeted antenatal screening to reduce vertical transmission from mothers to infants in the UK.
Topics: Humans; HTLV-I Infections; Female; Pregnancy; Wales; Cost-Benefit Analysis; Human T-lymphotropic virus 1; England; Infectious Disease Transmission, Vertical; Prenatal Diagnosis; Mass Screening; Pregnancy Complications, Infectious; Infant; Infant, Newborn; Adult
PubMed: 38818747
DOI: 10.2807/1560-7917.ES.2024.29.22.2300537 -
Scientific Reports May 2024Adult T-cell leukemia/lymphoma (ATL) occurs after human T-cell leukemia virus type-1 (HTLV-1) infection with a long latency period exceeding several decades. This...
Adult T-cell leukemia/lymphoma (ATL) occurs after human T-cell leukemia virus type-1 (HTLV-1) infection with a long latency period exceeding several decades. This implies the presence of immune evasion mechanisms for HTLV-1-infected T cells. Although ATL cells have a CD4CD25 phenotype similar to that of regulatory T cells (Tregs), they do not always possess the immunosuppressive functions of Tregs. Factors that impart effective immunosuppressive functions to HTLV-1-infected cells may exist. A previous study identified a new CD13 Treg subpopulation with enhanced immunosuppressive activity. We, herein, describe the paired CD13 (designated as MT-50.1) and CD13 (MT-50.4) HTLV-1-infected T-cell lines with Treg-like phenotype, derived from the peripheral blood of a single patient with lymphoma-type ATL. The cell lines were found to be derived from HTLV-1-infected non-leukemic cells. MT-50.4 cells secreted higher levels of immunosuppressive cytokines, IL-10 and TGF-β, expressed higher levels of Foxp3, and showed stronger suppression of CD4CD25 T cell proliferation than MT-50.1 cells. Furthermore, the CD13 inhibitor bestatin significantly attenuated MT-50.4 cell growth, while it did not for MT-50.1 cells. These findings suggest that CD13 expression may be involved in the increased Treg-like activity of MT-50.4 cells. Hence, MT-50.4 cells will be useful for in-depth studies of CD13Foxp3 HTLV-1-infected cells.
Topics: Humans; T-Lymphocytes, Regulatory; Human T-lymphotropic virus 1; Leukemia-Lymphoma, Adult T-Cell; CD13 Antigens; HTLV-I Infections; Cell Line
PubMed: 38822041
DOI: 10.1038/s41598-024-63494-x -
The Journal of Veterinary Medical... Jun 2024The present study analyzed B-cell clonality and bovine leukemia virus (BLV) provirus integration sites in cattle with enzootic bovine leukosis (EBL) having BLV proviral...
The present study analyzed B-cell clonality and bovine leukemia virus (BLV) provirus integration sites in cattle with enzootic bovine leukosis (EBL) having BLV proviral copy numbers less or greater than the number of bovine nucleated cells. EBL cattle with BLV copy numbers less than the number of bovine nucleated cells showed monoclonal and biclonal proliferation of B-cells with one BLV provirus integration site. On the other hand, EBL cattle with BLV copy numbers greater than the number of bovine nucleated cells showed monoclonal proliferation of B-cells with two BLV provirus integration sites. These results suggest that superinfection of BLV can occur in EBL cattle.
Topics: Animals; Leukemia Virus, Bovine; Enzootic Bovine Leukosis; Cattle; Proviruses; DNA, Viral; B-Lymphocytes; Virus Integration; Cell Proliferation
PubMed: 38631888
DOI: 10.1292/jvms.24-0037