INVESTIGATION OF PHYTOHEMAGGLUTININ-INDUCED AGGLUTINATION OF RAT ERYTHROCYTES: EFFECT OF ATP AND OTHER BIOLOGICALLY ACTIV SUBSTANCES

In studying the dynamics of biomembrane organization, the interaction between a lectin and specific membrane receptor is one of the important subjects. Although a lot of reports has dealt with the agglutination induced by phytohemagglutinins, the real mechanism is still not clear. In recent years, Singer et al. have carried out a series of experiments on this aspect of the relationship between metabolic status and lectininduced agglutination and indicated ATP could increase the agglutination of human erythrocytes induced by PHA-P.In this paper we reported the results concerning ATP and related biologically active substances on agglutination of rat erythrocytes estimated by spectrophotometric analysis. PHA at the concentration of 125μg/ml could induce the agglutination of erythrocytes in 45.9% after incubating 2.5×10~8 cells for 120 minutes under 37℃. ATP could increase the effect to 76.4% at the concentration of 4mM. But it has been found that ATP itself could induce the agglutination directly by 32.7 %. When half the amount of ATP and PHA (i. e. 2mM and 62.5μg/ml respectively) was administered, the agglutination percentage was 42.8%; it was very similar to that induced by afull dose of PHA alone. Therefore it is considered that increase of agglutination was due to the cumulative effect of these two agents instead of synergistic or promoting action. ADP and AMP possessed the similar effect, while adenosine did not.The antitumor alkaloid 10-hydroxycamptothecin at 500μg/ml could induce the agglutination of erythrocytes in 41%, but it did not influence PHA-induced aggluti nation. Vincristine, homoharringtonine and 8-brom-cAMP all have no effect on the agglutination.