EF1a-CD81-tdTomato Lentivirus

The EF1a-CD81-tdTomato lentivirus is a versatile research-grade vector designed for constitutive expression of the CD81-tdTomato fusion protein under the control of the human EF1α promoter. The EF1α promoter is widely recognized for its strong and relatively ubiquitous activity in various cell types, including many primary cells and stem cell-derived cell lines, and its resistance to silencing compared to some viral promoters in long-term studies. This system utilizes a modern self-inactivating lentiviral backbone, supporting stable genomic integration for persistent expression in both dividing and non-dividing cells, while maintaining replication-deficient safety under standard laboratory conditions. The CD81 portion is a well-characterized tetraspanin protein enriched in the plasma membrane, multivesicular bodies, and extracellular vesicles (EVs), enabling precise membrane and EV targeting; while the tdTomato fluorescent protein provides a bright, rapidly maturing, and photostable red fluorescent signal with minimal cytotoxicity and reduced background interference from cellular autofluorescence.

Researchers can use the tdTomato signal as a built-in traceable reporter for CD81-positive vesicles to visualize and quantify EV biogenesis, cargo sorting, transport through multivesicular bodies, vesicle release, and uptake by recipient cells. This construct is ideal for live-cell confocal or spinning disk microscopy, high-content imaging, in vivo microscopy, and fluorescence particle analysis workflows, enabling dynamic studies of EV dynamics and intercellular communication in co-cultures and complex microenvironments. In oncology and immunology, it supports mapping tumor-stroma and tumor-immune cell interactions mediated by CD81-rich vesicles, monitoring EV-mediated signaling pathway remodeling and drug resistance, and studying membrane microdomains of tetraspanin organization. In cell biology, it facilitates the analysis of membrane organization, endocytosis, cell migration, and cell-cell contact without interfering with the nucleus, while the stable red fluorescence simplifies long-term lineage tracing and clonal selection.