en عمومى General پژوهشي Original article Background and Aims: During the last years a new Foreskin cell line strain (RFSC) has been isolated, characterized and stored in a representative cell bank stock in liquid nitrogen as a part of HCB (Human Cell Bank) development program in Razi institute. Materials and Methods: The cell population was serially passaged for mass production purpose based on WHO schedule .The controls on pool samples were carried out upon our sampling method and international recommendations. Results: The data concerning parameters as well as the result of compulsory controls on Kario logy oncogenicity, cross contaminations, species specificity, no oncogenicity, and mycoplasma free of a human cell line that contained heteroploid chromosomal characterizations are performed. Conclusion: Kariological examination found an obvious discrepancy in the frequency of aberrations due to high passage level that produced a heteroploid continuous cell line. Virus susceptibility shows RFSC-1 more sensitive to RS#12 Mumps virus strain. This cell line is completely sterile and has no any cross contamination to other pathogen and can be used for production and control of Mumps vaccine. Primary culture, Cell Characterization, Human Cell Bank, RFSC-1 7 13 http://journal.isv.org.ir/browse.php?a_code=A-10-43-1&slc_lang=en&sid=1 N Mahmudi-Gharoeie 10031947532846003360 10031947532846003360 No Genetic Department, Shahrekord University Faculty of Science, Shahrekord, Iran A Mohammadi a.mohammadi@rvsri.ac.ir 10031947532846003361 10031947532846003361 Yes Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran B Saffar 10031947532846003362 10031947532846003362 No Genetic Department, Shahrekord University Faculty of Science, Shahrekord, Iran F Esna-Ashari 10031947532846003363 10031947532846003363 No Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran A Foroghi 10031947532846003364 10031947532846003364 No Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran B Alirezaee 10031947532846003365 10031947532846003365 No Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran R Ghorbani 10031947532846003366 10031947532846003366 No Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran ZA Sedigh 10031947532846003367 10031947532846003367 No Human Viral Vaccine Department, Razi Vaccine and Research Institute, Alborz Karaj, Iran