ELECTROPERMEABILIZATION OF PERIPHERAL-BLOOD PHAGOCYTES INDUCES A LONG-LIVED CELL-MEMBRANE ALTERATION WHICH DOES NOT AFFECT THEIR VIABILITY

Electropermeabilization is an efficient tool for introduction of molec ules into cell cytoplasm. Blood cells can then be loaded with drugs to build new immunocompatible vehicles. The aim of this study was to eva luate the functional modifications of electropulsed phagocytes by moni toring the oxygenating activities. Chemiluminescence measurements were performed on blood samples after stimulation (addition of phorbol myr istate acetate or opsonized zymosan). Results show that: when ten puls es of 1.6 kV cm(-1) lasting 100 mu s were applied (resulting in permea bilization of 70% of leucocytes and 44% of membrane area), an alterati on in the peak of chemiluminescence and in the delay time of the react ion are observed, after phorbol 12-myristate 13-acetate stimulation. P ulsation under other conditions (two pulses of 1.2 kV cm(-1) lasting 1 ms) led to the same permeabilization yield but affected a smaller cel l membrane area (25%) and did not impair oxygenating activities for ei ther stimulation. Results were similar if stimulation was triggered 7 h after electropulsing. A long-lived functional alteration is present when strong fields with short duration are used, affecting a large cel l surface. Low-field long-pulse electropulsation led to better preserv ation of physiological. integrity of the permeabilized phagocytes.