Red cell-mediated microinjection

Red cell-mediated microinjection facilitates the rapid introduction of macromolecules into large numbers of culture cells. Efficient injection of cells in monolayer using PEG as fusogen can be accomplished using any of three alternative agglutinating agents (PHA, Con A, or polylysine) to attach loaded red cells to recipient cells. These three method yield similar efficiencies of microinjection and postfusion viability, as shown in Table I. Either of the methods, after being tailored to fit particular needs, can be expected to produce results similar to those in Table I with some variability due to differences in cell types. One drawback when PHA is used as agglutinin is the inability to remove adherent, nonfused red cells from cultures after fusion. Reversible attachment of red cells is possible using Con A or polylysine. For each of the latter agglutinins, reversal of binding detaches the great majority of the red cells; virtually all nonfused red cells may be eliminated by performing an additional simple step in either case.