Chromosomal Variation in Three Human-Mouse Hybridoma Cell Lines after Various Passaging Intervals as Assessed with Two Different Staining Methods

The main objective of this study was to investigate the status of chromosome stability in 3 human-mouse hybridoma cell lines over a period of time in various passages.Metaphase spreads from 3 human-mouse cell lines (HF2X653, SPMO-4 and F3B6) that had been cultured in 4 successive passages, from 1 to 4 weeks, were prepared and analyzed. Metaphase chromosomes stained in Giemsa and a fluorescent dye, Hoechst 33258, for differential staining. This staining was performed for differentiating human and mouse chromosomes.Numerical chromosome analysis showed that although in successive passages the total number of chromosomes in hybridoma cells remained unchanged, some changes occurred in the number of human and mouse metacentric and acrocentric chromosomes during different passages. These changes were detectable, using fluorescence staining method. Since one of the main uses of human-mouse hybridoma cells is producing monoclonal antibody, chromosomal instability in these cells causes the loss of human chromosomes coding the antibody of interest occasionally. Therefore, cytogenetical analysis and characterization of these cells, especially by using the appropriate ways of chromosomal identification, is essential prior to use.