Specific cell binding using staphylococcal protein A magnetic microspheres.

Protein A, a protein derived from Staphylococcus aureus, was incorporated into the matrix of magnetic albumin microspheres. Because staphylococcal protein A binds most subclasses of immunoglobulin G through their Fc portions, immunoglobulin may be rapidly bound to microspheres without chemical coupling agents or a diamino-heptane spacer group. Microspheres so prepared bind specifically to a given cell type when incubated in vitro with a heterogeneous cell population. The use of these microspheres as a drug carrier capable of cellular specificity as well as their ability to isolate homogeneous cell populations rapidly is discussed.