HIGHLY SPECIFIC SEPARATION OF HETEROGENEOUS CELL-POPULATIONS BY LECTIN-COATED BEADS - APPLICATION FOR THE ISOLATION OF INNER MEDULLARY COLLECTING DUCT CELLS

Conditions for the highly specific selection of a cell type by the use of lectin-coated magnetic beads are reported for the isolation of inn er medullary collecting duct (IMCD) cells from a heterogeneous inner m edullary cell suspension, containing both single cells and tubular fra gments of variable size. The lectin Dolichos Biflorus Agglutinin (DBA) , which binds in rat inner medulla exclusively to IMCD cells, was coup led via the avidin-biotin system to beads. By isolating DBA-bead-IMCD cells in a magnetic field (positive selection) from a suspension conta ining about 50% IMCD, a fraction of 98 +/- 1% purity was obtained; rec overy of cells was up to 90%. Suspensions negative on reverse-transcri ptase polymerase chain reaction for vimentin as a marker of contaminat ing interstitial and vascular cells could be received by repeating thi s procedure and additional trypsinization. On the other hand, it was p ossible to reduce the portion of IMCD cells in the suspension by one i solation step to 1.5 +/- 0.9% (negative selection). Performing this st ep twice resulted in virtually pure suspensions. No significant effect s of this isolation technique on cell viability, growth characteristic s, and biochemical parameters were observed. Therefore, this method ap pears to be a powerful tool for the highly specific separation of hete rogeneous cell populations.