[Karyologic research on murine B-cell hybridomas].

Karyotypes of 10 murine hybridomas producing monoclonal antibodies to microbal antigenes were examined using chromosome slides stained with Azur-eosine. Hybrid origin of all the cell clones was confirmed. The cultures differed from each other in modal chromosome numbers, in novel markers that were absent from cells of the parental myeloma X63.Ag8.653, in the frequency of metaphases with double minute chromosomes and in the level of cells with chromosome aberrations. The results obtained enable us to recommend a cytogenetic analysis for the identification of hybridomas. The following observations point out to a relative instability of the chromosomal apparatus of hybridomas: chromosome numbers varied significantly from cell to cell within one and the same clone; modal chromosome counts decreased in 3 of 5 hybridomas that were studied repeatedly within 1-2 months; in some hybridomas unstable chromosome aberrations were found in 18-38% of cells.