Preparation of PEG-grafted immunomagnetoliposomes entrapping citrate stabilized magnetite particles and their application in CD34+ cell sorting

摘要

Immunomagnetic systems have been used for positive selection of a cell fractionfrom a mixture using appropriate surface markers with satisfactory results, as haematopoietic CD34± cells. This work reports on the development of poly(etbylene glycol)-grafted (PEG) immunoliposomes loaded with citrate-magnetite stabilized particles as the separation vehicles for immunomagnetic separations. The magnetic ferrofluid was encapsulated into PEG-liposomes by the DRV methodology. The magnetoliposomes had a liposomal size of450nm and a Fe/lipid molar ratio of 1.52 + 0.26, and were retained in the magnetic field created by the MiniMACS system. Anti-CD34 immunomagne-toliposomes with 100 mAb/vesicle were prepared by coupling the MylO mAb and bound specifically for CD34-i- KG-la cells in culture and in mixtures with CD34—cells (CHO or JurkaQ. The magnetic cell sorting was carried out in cell mixtures KG-la/CHO or KG-la/Jurkat with different initial0o of CD34± Kg-la cells. For 106 positive cells and 100 jiM of immunomagnetoliposomes, the capture efficiency xvas > 85% and independent of the starting percentage of CD34 -1- cells. The decrease of the final purity, when the starting percentage of CD34+ cells decreases and, dependent of the CD34— cell line used, point to the degree of non-specific cell binding of MylO-immunomagnetoliposomes as being crucial, among of the methodological aspects as the number of starting CD34± cells. The CD34+ cells isolated retained the viability with an estimated recovery of 45-50%.