Cell sorting microbeads as novel contrast agent for magnetic resonance imaging

Area of Science:

• Biomedical Engineering
• Cellular Imaging
• Immunotherapy

Background:

• Cell-based therapies and MRI necessitate effective cell tracking contrast agents.
• Labeling non-phagocytic cells like T cells for MRI remains a significant challenge.

Purpose of the Study:

• To develop and evaluate a novel, efficient method for labeling and tracking T cells, specifically regulatory T cells (Tregs), using magnetic resonance imaging (MRI).
• To assess the feasibility of using CD25 microbeads as a combined sorting and labeling agent for non-invasive in vivo cell tracking.

Main Methods:

• Compared CD25 microbeads to ferumoxytol for magnetic labeling of T cells.
• Investigated in vitro labeling efficiency of regulatory T cells (Tregs) using MRI.
• Performed in vivo tracking of CD25 microbead-labeled Tregs and T cells via intravenous injection, with liver MRIs at pre- and 24-hour post-injection time points.

Main Results:

• CD25 microbeads demonstrated T2 signal decay properties comparable to other iron oxide contrast agents.
• Readily internalized by Tregs, CD25 microbeads enabled dose-dependent T2 signal suppression detectable by MRI.
• Systemically injected, labeled Tregs were successfully detected in the liver 24 hours post-injection, unlike control T cells.

Conclusions:

• CD25 microbead-based labeling is an effective tool for Treg tagging, providing detectable MR signal changes in vitro and in vivo.
• This novel cellular tracking method is crucial for monitoring Treg behavior in inflammatory conditions and solid organ transplantation.