Effect of Extracellular Vesicles from HTLV-1 Infected Cells on Recipient Uninfected Cells

Abstract

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus known to cause diseases such as adult T-cell  leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Its global infection count has reached up to 10 million, with particularly high prevalence in regions like Japan, Africa, the Caribbean, and South America. HUT-102 (HuT-102), a cell line derived from ATL, is renowned for its aggressive cancer properties. Recent research has unveiled the critical role of Extracellular Vesicles (EVs) in promoting HTLV-1 transmission through cell-cell contact, providing new insights into its spread mechanisms. To deepen our understanding, we employed differential ultracentrifugation (DUC) at various speeds (2 k, 10 k, 100 k, 167 k/4 hours, and 167 k/16 hours) to isolate distinct subpopulations of EVs from infected cell supernatants. Notably, the 2 k subpopulation exhibited the highest abundance of viral/host proteins. Additionally, HTLV-1 EVs were found to induce the expression of migration-related cytokines in astrocytes and monocyte-derived macrophages. Moreover, EVs from both the 2 k and 10 k subpopulations significantly increased HTLV-1 spread in a humanized mouse model, emphasizing their importance in viral transmission and pathogenesis. In this study, we examine the uptake of recipient infected cells from HUT-102 infected Extracellular Vesicles (EVs). EVs were collected from HUT-102 infected cells and subsequently co-cultured with CEM (Uninfected) Cells on a 96-Well Assay Black Plate, differentiating the subpopulations accordingly. The analysis of the recipient cells from HUT-102 infected cells was performed at both 1-hour and 24-hour time points. Furthermore, it has been demonstrated that various populations of Extracellular Vesicles (EVs) derived from HTLV-1 infected cells are taken up by uninfected T-cells.