THE FUNCTION OF NEUTROPHILS ISOLATED BY A MAGNETIC ANTIBODY CELL-SEPARATION TECHNIQUE IS NOT ALTERED IN COMPARISON TO A DENSITY GRADIENT CENTRIFUGATION METHOD

Most comparative studies on neutrophil (PMN) isolation techniques have shown either activation or functional impairment of the cells due to the different separation processes. We have established a preparation method for PMN from human whole blood employing iron tagged, magnetiza ble antibodies against the cell surface antigen CD15. The aim of our s tudy was to test whether this magnetic separation (MACS) alters cellul ar functions of PMN in comparison to a conventional density gradient t echnique (Percoll). The purity, cell yield, and pre-activation of the cells were evaluated. The latter was assessed by quantifying the expre ssion of the integrin CD11b using flow cytometry. Furthermore, as func tional tests, cell morphology and the oxidative burst reaction were in vestigated. We have shown that the use of 'magnetic' antibodies leads to highly purified PMN (> 99% of isolated leukocytes), while there is still contamination by eosinophils (about 6%) after Percoll separation . Platelet contamination was about the same in both procedures (approx . one platelet per two PMN). The basal expression of CD11b and, hence, neutrophil activation, was significantly lower and the upregulation o f CD11b in response to FMLP was more pronounced after magnetic separat ion, as compared to density gradient centrifugation. The MACS techniqu e did not lead to polarisation of PMN, nor did it affect the oxidative burst. This study suggests that magnetic separation is a simple, time -saving technique, yielding highly purified and functionally intact PM N.