Treatment with chelating agent abolished stimulation of human lymphocyte blast transformation observed in the presence of native microbial glycoproteins. Heparin passed through a column packed with aluminum hydroxide inhibited cytotoxic activity in natural killer cells. We discuss the possibility of regulation of cell functions via modulation of the vector of transport and exchange of metal cations in cell microenvironment and the role of macromolecular compounds containing carbohydrate components in this process.