Mutagenesis of Mouse Myeloma Cells with ‘Melphalan’

Abstract

TECHNIQUES have been developed to study the potential mutagenic affects of various drugs on mouse myeloma cells. Cells from mouse plasmacytomas have been adapted to continuous culture, cloned in soft agar, and the clones have been overlayed with antisera specific for the immunoglobulin chains. The immunoglobulin secreted by the myeloma cells precipitates with the antibody in the agar surrounding the clones. Clones which have lost the ability to secrete immunoglobulin remain unstained by antigen-antibody precipitates and can be recovered and scored as variants¹. Mouse myeloma cells which produce IgG spontaneously lose the ability to produce heavy chains and produce light chains at a rate of 1.1 × 10⁻³ per cell per generation. The incidence of variants is not increased by treatment with the alkylating agent, ethyl methane sulphonate. Nitrosoguanidine causes a two-to-three-fold increase in variants while the acridine half mustard, ICR-191, which is effective in producing frame shift mutations in microorganisms², produces a twenty-fold increase in variants³.