HYBRID ANTIBODIES WITH DUAL SPECIFICITY FOR THE DELIVERY OF RICIN TO IMMUNOGLOBULIN-BEARING TARGET-CELLS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (6) , 2073-2078
Abstract
Hybrid antibodies possessing 1 binding site for the toxic lectin ricin and a companion site directed against human Ig were constructed in vitro. This bifunctional reagent specifically attached to human lymphocyte surface Ig determinants and, thus situated, could simultaneously capture ricin molecules or its toxic A chain. Attachment of these components to the cell was revealed by specific fluorescein-labeled antibodies. Once concentrated at the target cell membrane, hybrid-bound toxin was subsequently released to function via its normal mechanism of biological action. It gained access to ribosomes, its intracellular target, and curtailed protein synthesis. Toxicity was not augmented for Ig-negative cells to which hybrid could not bind and free human IgG could competitively block the enhanced effects observed for Ig-bearing cell lines. Hybrid antibodies may be utilized to carry active agents within close proximity to the membrane of a specified cell type [such as a tumor cell] and thereby selectively enhance their effect.