GOLD BINDING-SITES IN RED-BLOOD-CELLS

Gold distribution and binding sites in blood and red blood cells (RBCs ) have been determined. RBCs were separated from plasma and lysed. The cytosol was separated from membranes which were then solubilized via detergents. Total gold in each fraction was measured via flow injectio n analysis (FIA) with inductively coupled plasma mass spectroscopy (IC P-MS) detection. Various high-performance liquid chromatography (HPLC) techniques such as ion-pairing, reversed-phase and size-exclusion chr omatography have been applied to RBC samples prepared by incubation wi th specific compounds and to RBCs from rheumatoid arthritis (RA) patie nts. Preliminary studies of RA patients' samples indicate very differe nt gold uptake into RBCs depending on the particular patient. Size-exc lusion chromatography indicates that gold in the lysate is not bound p rincipally to hemoglobin but rather to a significantly higher molecula r weight species (about 330 000 Da). Low molecular weight species in t he ultrafiltered RBC lysate include the dicyanogold(I) anion and possi bly the bis(glutathione)gold(I) complex. Incubation experiments have b een designed to measure dicyanogold(I) and gold drug uptake by RBCs. E xperiments with 4,4'-diisothiocyanatostilbene-2,2'-D,L-sulfonic acid ( DIDS), an anion channel blocker, indicate that dicyanogold(I) enters t he cell by some path other than the anion channel. The inhibition of g old uptake on addition of free cyanide suggests that the loss of cyani de from dicyanogold(I) is important in dicyanogold(I) uptake by RBCs. Given the rapid uptake of dicyanogold(I) and its apparently high toler ance in humans, this material is suggested as a possible therapy in th e treatment of AIDS.