[Mg2+-dependent doxycycline-induced inhibition of leukocyte adhesion]

The method for estimating in vitro leukocyte adhesion was modified in relation to investigation of the effect of antibiotics and other pharmacological agents on cell activation. The adhesion intensity was estimated in standard 96-cavity microplates from the content of beta-hexosaminidase in the adherent cells. That made it possible to easily automatize the method by using the equipment for enzyme immunoassay. It was shown that spontaneous and induced adhesion of guinea pig leukocytes depended on temperature and bivalent ions. The level of spontaneous adhesion mainly depended on Mg ions. Doxycycline, 0.1 to 100 micrograms/ml, did not induce degranulation of leukocytes and had no cytotoxic action. Doxycycline in supratherapeutic concentrations (greater than 10 micrograms/ml) inhibited the spontaneous leukocyte adhesion. In special experiments it was found that the doxycycline's inhibitory effect was partially reversible and associated with ++chelation of Mg ions rather than Ca ones.