Changes in oligosaccharides of human blood cells measured by tritium- and FITC-labeled lectins after in vitro- and in vivo-irradiation--lectin binding as a 'biological dosemeter'?

The lectin-binding system has been described previously as a biological dosimeter, by revealing induced changes in oligosaccharides of the cell membrane. The measurements were performed by binding [3H]concanavalin A to blood cells. Our results on human blood cells irradiated in vitro with doses in the range 0.5-5 Gy indicate great difficulties in using radioactive labeled Con-A for an accurate quantitative analysis of radiation effects on cell membranes. It appears nearly impossible to differentiate between only a few damaged cells and the remaining undamaged cells. Using fluorescein-labeled Con-A and wheat germ agglutinin, single-cell measurements of fluorescence intensity by flow cytometry revealed enhanced lectin-binding to platelets, lymphocytes and monocytes in the dose range 0.5-5 Gy after in vitro irradiation. But even by this method it was impossible to discriminate irradiations in either partial or whole-body irradiated patients. There were no significant or reproducible changes in the binding capacities of the blood-cell membranes of these patients. Therefore, the suitability of lectin binding as a 'biological indicator' for irradiation could not be confirmed.