R&D Systems now offers a MagCellect Rat CD4⁺CD25⁺ Regulatory T Cell Isolation Kit (Catalog #MAGR304). This kit is designed to isolate CD4⁺CD25⁺ regulatory T (Treg) cells using a two-step procedure that combines both negative and positive selection techniques. CD4⁺ T cells are initially isolated by negative selection whereby unwanted cells are tagged and magnetically removed. CD4⁺ T cells remain in suspension and are subsequently combined with a biotinylated rat CD25 antibody and streptavidin ferrofluid to specifically tag and isolate CD4⁺CD25⁺ Treg cells by positive selection. The kit includes sufficient reagents to process 1 x 10⁹ total cells. The resulting cell preparation is highly enriched for CD4⁺CD25⁺ T cells with a purity of recovered cells ranging between 75-85%.

Isolation of Regulatory T Cells using the MagCellect Rat CD4+CD25+ Regulatory T Cell Isolation Kit. CD4+ T cells (Step 1) and CD4+CD25+ regulatory T cells (Step 2) were isolated from rat splenocytes using the MagCellect Rat CD4+CD25+ Regulatory T Cell Isolation Kit (Catalog # MAGR304). Following the first and the second isolation steps in the kit protocol, the cells were stained with the indicated antibodies and detected by flow cytometry. CD25+ T cells are typically a heterogeneous population that expresses different levels of CD25. Both CD25dim and CD25high cells are isolated with this kit.