The specific inhibition of cellular clonogenic proliferation using ²¹¹At labelled lectins and antibodies-I

A monoclonal antibody with a broad anti-human leucocyte specificity, designated BK 19.45 and the plant lectin Concanavalin A have been labelled with the α-emitting cyclotron produced radiohalogen astatine-211. Both human and murine tumour cell lines and human leukemic bone marrow samples have been specifically labelled with these radioactive proteins. In all cases the amount of ²¹¹At bound to the cells is directly correlated with a decrease in cellular reproductive potential as shown by the ability of the cells to proliferate in a clonogenic assay. For the labelled monoclonal antibody experiments, the radiation dose needed to yield 37% cell survival, the D₃₇ dose, may be achieved with an averaged of 12²¹¹ At atoms/cell.