Serum inhibition of in vitro 67Ga binding by L1210 leukemic cells.

The influence of human serum on in vitro 67Ga uptake by L1210 leukemic lymphoblasts has been investigated. Both high- and low-molecular-weight serum components inhibit cellular uptake of the isotope. Inhibition by the high-molecular-weight serum fraction correlates closely with the extent of binding of the radionuclide. Although transferring participates in high-molecular-weight inhibition, it accounts for 10 percent or less of the inhibitory and binding capacity. Similarly, various low-molecular-weight serum components, including citrate, phosphate, glutamate, and others, contribute to inhibition. This inhibition of 67Ca uptake by serum results from the presence of several, perhaps many, inhibitory components.