Effect of immunomodulating agents on leucocyte chemotaxis and cyclic nucleotides.

We have studied the effect of immunomodulating agents on polymorphonuclear leucocyte chemotaxis and their relation to the modification of cyclic nucleotide levels. The tested drugs (levamisole, tuftsin, azimexon, muramyl dipeptide, isoprinosine) inhibited the chemotaxis of 'normal' cells but restored the impaired chemotactic responsiveness of inflammatory cells. None of these drugs had any significant effect on cyclic nucleotide levels in 'normal' cells. All the drugs, except isoprinosine, produced an increase in the cGMP levels in inflammatory cells. These results suggest that immunomodulators are able to modify PMN chemotaxis. This effect cannot, however, be related to modification of the cyclic nucleotide levels.