SAMM 368, a plasmacytoma which produces IgA-κ and IgG2b-κ was established in vitro from primary explants or after animal passage. The 9 lines that were established produced both paraproteins. The production of both immunoglobulins by single cells was demonstrated by immunofluorescent staining and cloning. Continuous culture of 3 parent lines for 18 months and 11 cloned lines for periods from 5 to 7 months demonstrated that double production is a stable characteristic of this plasmacytoma.
Two single paraprotein-producing varients (IgG2b or IgA) were derived when cells were cultured in the presence of Fungizone.
Chromosomal analysis of SAMM 368 indicates that this double producing tumor has a modal number similar to those observed in myelomas producing a single immunoglobulin class.
This work was supported in part by United States Public Health Service Grants AI 11502 and CA 16673.