Genetic Stability Of Immortalized Cell Line Of Lymphocytes Transformed By EB Virus After Long Subculturing Process

B lymphoid cells from human peripheral blood can be transformed into actively proliferating immortalized cell line by Epstein-Barr virus(EBV).The immortalized cell line,as sources of DNA and cells,are used widely in researches in etiology, immunology and cellular biology.Therefore,in order to ensure reproducible results and continuity in research of life science:it is important for immortalized cell line to remain its genetic stability,even after a long subculture process.In the present study,the genetic stability including chromosome diploidy, microsatellite DNA and telomerase activity were evaluated.We calculate the frequencies of hyperdiploid,hypodiploid and polyploidy of immortalized cell line with the chromosome banding techniques every 10 passages.For 13 STR loci with a mutation rate＞0.09%in nuclear genome and 2 STR loci with a high-frequency mutation in D-loop of mitochondrial genome,the arnplication products of DNA extracted from the blood and the cell line every 10 passages were detected by polyacrylamide gel electrophoresis(PAGE).During the subcultureing process,the telomerase activity in the cell lines were detected by telomerase assay kit.The results showed that the immortalized cell line remained genetically stable within 30 passages.After the 30 passages,the growth rates of cell lines slowed down, the number of cell cycle phases decreased.The cell lines Yao56 and 43 changed into polyploidy after 30 and 60 passages,and the cell lines Yao 225 and 230 died after the 50 passages.No mutation was identified in 15 high-frequency mutation STR loci before 80 passages,except cell line Yao262.One mutation was detected in the STR locus D13S317 of the cell line Yao262 at the passage 60.The telomerase activity was negative before 80 passages.