The aggregation between lectins and lymphocyte surface receptors can be affected strongly by a low-level electric field induced in the cell suspension by a time-varying magnetic field. One of the possible mechanisms is the microelectrophoretic effect due to the electric field, which influences the distance (in the mean square sense) between charged ligands and receptors when they are about to separate. On a purely theoretical basis, it is shown that, at low frequencies, an externally induced periodic electric field always decreases the mean lifetime of ligand-receptor complexes. As a consequence, the mitogenic gain obtained by lectin addition to cell suspension is decreased. These results suggest that such a mechanism, if effective, reduces the lectin mitogenic capability and offers a way of handling similar phenomena which have been described for other biological systems.