A SIMPLE METHOD FOR NEGATIVE AND POSITIVE SELECTION OF MURINE AND HUMAN IGM-BEARING LYMPHOCYTES BASED ON THE USE OF ANTIBODY-COATED SILICA MICROPARTICLES

The use of octadecyl silica microparticles is proposed as an alternati ve method for negative and positive selection of IgM-bearing lymphocyt es. SiCl8 microparticles coated with affinity purified IgG anti-IgM we re evaluated in their efficiency to deplete IgM-bearing cells. 6 mg of SiCl8-IgG depleted an average of 97% IgM-bearing cells from a murine spleen cell suspension and of 84% IgM-bearing cells from human spleen cells. The viability of the selected cells was not affected by this pr ocedure. We also analyzed the ability of whole serum to release IgM-be aring cells from the complex SiCl8-target cell. The IgM releasing effi ciency was 98%, with a resulting viability of 85%. These results indic ate that SiCl8 microparticles, saturated with specific antibodies, may be used as an alternative method for depletion or purification of cel ls bearing the corresponding antigen, from complex cell suspensions. T he method is simple, efficient and inexpensive, representing an intere sting alternative to the immunomagnetic selection.