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Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy of CD4+ T lymphocytes caused by human T lymphotropic virus type-1 (HTLV-1) infection. HTLV-1 was brought to the World Health Organization (WHO) and researchers to address its impact on global public health, oncogenicity, and deterioration of the host immune system toward autoimmunity. In a minority of the infected population (3–5%), it can induce inflammatory networks toward HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), or hijacking the infected CD4+ T lymphocytes into T regulatory subpopulation, stimulating anti-inflammatory signaling networks, and prompting ATLL development. This review critically discusses the complex signaling networks in ATLL pathogenesis during virus–host interactions for better interpretation of oncogenicity and introduces the main candidates in the pathogenesis of ATLL. At least two viral factors, HTLV-1 trans-activator protein (TAX) and HTLV-1 basic leucine zipper factor (HBZ), are implicated in ATLL manifestation, interacting with host responses and deregulating cell signaling in favor of infected cell survival and virus dissemination. Such molecules can be used as potential novel biomarkers for ATLL prognosis or targets for therapy. Moreover, the challenging aspects of HTLV-1 oncogenesis introduced in this review could open new venues for further studies on acute leukemia pathogenesis. These features can aid in the discovery of effective immunotherapies when reversing the gene expression profile toward appropriate immune responses gradually becomes attainable. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a multifactorial life-threatening disease which an epidemiologic study in Northeastern Iran showed its association with HTLV-1 infection. Therefore, a cross-sectional study of 39 newly diagnosed subjects with angiography test in three groups including 14 coronary artery disease+HTLV-1+ (CAD+HTLV-1+), 8 CAD−HTLV-1+, and 17 CAD+HTLV-1- patients and 11 healthy subjects (CAD−HTLV-1-) were conducted. In the present study, Tax and proviral load (PVL) as HTLV-1 virulence factors, along with host chemokine receptor 1 (CCR1), and CCR2 were investigated. Real-time PCR TaqMan method was carried out for PVL measurement and HTLV-1- Tax , CCR1 , and CCR2 expressions in peripheral blood mononuclear cells (PBMCs). Furthermore, the main risk factors, lipid profile, and complete blood count (CBC) were assessed. Expression of CCR1 in CAD+HTLV-1+ group was higher than CAD−HTLV-1+ (P = 0.01) and healthy subjects (P = 0.02). Expression of CCR1 in CAD+HTLV-1+ was higher in comparison with CAD+HTLV-1-group but did not meet 95% CI (P = 0.02), but meaningful at 91% CI. In addition, expression of CCR2 in CAD+HTLV-1+ subjects was higher than CAD−HTLV-1+ and CAD+HTLV-1- (P = 0.001, P = 0.005, respectively). In CAD+HTLV-1- subjects, CCR2 was higher than CAD−HTLV-1+ (P = 0.03). The mean PVL in CAD+HTLV-1+ group is more than CAD−HTLV-1+ (P = 0.041). In HTLV-1+ patients Tax had a positive correlation with cholesterol (R = 0.59, P = 0.01), LDL (R = 0.79, P = 0.004) and a negative correlation with HDL (R = −0.47, P = 0.04). These correlations were stronger in CAD+HTLV-1+. Findings showed that HTLV-1 could alter the expression of CCR2 and, less effect, on CCR1. Moreover, the strong correlation between CCR2 and HTLV-1- Tax with cholesterol, LDL and HDL showed that Tax as the main HTLV-1 virulence factor in cytokine deregulation might be had indirect effects on cholesterol, LDL, and HDL levels. • Findings showed that HTLV-1 could change the expression of CCR2. • Tax there was the main virulence of cytokine deregulation, can affect cholesterol, LDL, and low HDL levels. • Expression of CCR1 and CCR2 in CAD+HTLV-1+ group was higher than CAD−HTLV-1+. [ABSTRACT FROM AUTHOR]

There is an urgent need to find an effective therapy for life-threatening HTLV-1-associated diseases. Bitter melon (Momordica charantia) is considered a traditional herb with antiviral and anticancer properties and was tested in this study on HTLV-1 infectivity. GC–MS analyzed the alcoholic extract. In vitro assay was carried out using transfection of HUVEC cells by HTLV-1-MT2 cell line. The cells were exposed to alcoholic and aqueous extracts at 5,10, and 20 µg/mL concentrations. In vivo, mice were divided into four groups. Three groups were treated with HTLV-1-MT-2 cells as test groups and positive control, and PBS as the negative control group in the presence and absence of M. charantia extracts. Peripheral blood mononuclear cells (PBMCs), mesenteric lymph nodes (MLNs), and splenocytes were collected for HTLV-1-proviral load (PVL) assessment, TaqMan-qPCR. The GC–MS analysis revealed 36 components in M. charantia. The studies showed significant reductions in HTLV-1-PVL in the presence of extract in the HUVEC-treated groups (P = 0.001). Furthermore, the inhibitory effects of extracts on HTLV-1 infected mice showed significant differences in HTLV-1-PVL among M. charantia treated groups with untreated (P = 0.001). The T-cells in MLNs were significantly more susceptible to HTLV-1 than others (P = 0.001). There were significant differences among HTLV-1-infected cells in MLNs and splenocytes (P = 0.001 and 0.046, respectively). Also, aqueous and alcoholic extract-treated groups significantly affected HTLV-1-infected PBMCs (P = 0.002 and 0.009, respectively). M. charantia may have effective antiviral properties. The substantial compound of M. charantia could have inhibitory effects on the proliferation and transmission of HTLV-1 oncovirus. [ABSTRACT FROM AUTHOR]

HTLV-1 causes two life-threatening diseases: adult T-cell leukaemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Due to the lack of proper treatment, an effective HTLV-1 vaccine is urgently needed. DNA sequences of 11–19 and 178–186 amino acids of HTLV-1-Tax and SP2 and P21 were fused to the mouse-Fcγ2a, or His-tag called tTax-tEnv:mFcγ2a and tTax-tEnv:His, respectively. These constructs were produced in Pichia pastoris , and their immunogenicity and protective properties were assessed in a mouse challenging model with an HTLV-1-MT2 cell line. The immunogenicity assessments showed significant increase in IFN-γ production in animals receiving tTax-tEnv:mFcγ2a (1537.2 ± 292.83 pg/mL) compared to tTax-tEnv:His (120.28 ± 23.9, p = 0.02). IL-12 production also increased in group receiving tTax-tEnv:mFcγ2a than tTax-tEnv:His group, (23 ± 2.6 vs 1.5 ± 0.6, p = 0.01), respectively. The IFN-γ and IL-12 levels in the Fc-immunised group were negatively correlated with PVL (R = -0.82, p < 0.04) and (R = -0.87, p = 0.05), respectively. While, IL-4 was increased by tTax-tEnv:His (21.16 ± 1.76 pg/mL) compared to tTax-tEnv:mFcγ2a (13.7 ± 1.49, p = 0.019) with a negative significant correlation to PVL (R = -0.95, p = 0.001). The mouse challenging assay with tTax-tEnv:mFcγ2a showed 50 % complete protection and a 50 % low level of HTLV-1-PVL compared to the positive control receiving HTLV-1-MT2 (p = 0.001). Challenging experiments for the His-tag protein showed the same outcome (p = 0.002) but by different mechanisms. The Fc-fusion construct induced more robust Th1, and His-tag protein shifted more to Th2 immune responses. Therefore, inducing both T helper responses, but a Th1/Th2 balance in favour of Th1 might be necessary for appropriate protection against HTLV-1 infection, spreading via cell-to-cell contact manner. [ABSTRACT FROM AUTHOR]