Re: First batch of H1N1 vaccine is ready to begin testing process. No vaccine for distribution before Fall 2009
Experimental Researches on Carcinogenesis or Tumorigenicity of MDCK Canine Kidney Cell(CKC) Lines and Analysis of Their Chromosome Karyotypes
The chromosomal number variations & structural aberrations of the MDCK cell line, primary feline or canine kidney cell(FKC or CKC) and Hela cell line were investigated and their karyotypes of conventional chromosome bands were analyzed.
The carcinogenesis or tumorigenicity testing of these cell lines in about 232 nude mice and for colony formation in soft agarose and for haemagglutination under different concentration of plant lectins of these cells were carried out.
Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with tetrapioid YA strain of MDCK cell during 20 - 45 passages, with hypodiploid JB strain of MDCK cell on passage 25, with di-and hypoploid JC strain of MDCK cell during 2 - 15passages or with hypoploid M strain of MDCK cell during 9 - 27 passages was 28/58, 1/5, 4/18 and 0/31,respectively.
The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high (mcs + n) and lowest (mcs)passages was not more than 5 % - 15 % and the structure aberrations was generally 0 - 3%.
These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome karyotype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid.
The repeatedly frozen, thawed and split controls of tumorigenicity-positive cell lines(X strain of Hela, M strain of BHK-21, JA strain of Vero, YA strain of MDCK)
have much lower tumorigenicity or are even non-carcinogenesis, and
the repeatedly frozen, thawed and split controls of very low tumorigenicity cell lines (M or JC strain of MDCK) are certainly non-carcinogenic and never have increased tumorigenicity.
It is thus evident that MDCK cell of M, JB or JC strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA strain can not be approved as substrate for the preparation of comattenuated viral vaccines.
In summary, all strains of MDCK cell line have tunorigenicity, at least have low tumorigencity, never have non-cancinogenic MDCK, but very
low tumorigenicity MDCK cell strains can certainly be used for the approval production of canine viral vaccines if the DNA content in viral cell cultures was remarkably decreased through conventional means in manufacturing process.
Therefore, the master cell stock and working cell bank of MDCK line used for vaccine manufacture were established in China, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity.
Tests showed that there were correlations among cell line chromosome number variations, anchorage independence in soft agarose, haemagglutination under plant lectins, and tumor-forming ability in nude mice, thus all the in vitro tests are economic, simple and reliable means for monitoring the tumor-forming ability of MDCK line in nude mice.
作 者：ZHANG De-Li LI Liu-jin XIA Geng-tian HE Xu-yu GAO Bu-xian BAI Xiao-hong HUANG Gao-sheng LIU Shang-gao YAN Long-Fei FANG Fu-de
作者单位：ZHANG De-Li(Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100083, P. R.China;Beijing Institute of Preventive Medicine,Beijing 100071,P.R.China;Department of Pathology at School of Pre-clinical Education,)
LI Liu-jin,BAI Xiao-hong(Department of Toxicology at Center for Research Development of Animal Healthcare Products, Fourth Military Medical University, Xian 710032, P. R . China)
XIA Geng-tian,HE Xu-yu,GAO Bu-xian(Beijing Institute of Preventive Medicine,Beijing 100071,P.R.China)
HUANG Gao-sheng,YAN Long-Fei(Department of Pathology at School of Pre-clinical Education, Section of Pathology at Xi-Jing Hospital, Institute for Cancer Research at China Cancer Research Foundation, Fourth Military Medical University, Xian 710032, P. R . China)
LIU Shang-gao(Key Open Laboratory of Preventive Veterinary Medicine of State Ministry of Agriculture, College of Animal Medical Sciences State Key Laboratory of Agricultural Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100094, P)
FANG Fu-de(State Key Laboratory of Medical Molecular Biology, School of Basic Medical Sciences at the Peking Union Medical Colloge/Institute of Basic Medical Sciences at the Chinese Academy of Medical Sciences, Beijing 100005, P.R. China)
http://d.wanfangdata.com.cn/Periodical_zgnykx-e200207017.aspx
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How these Chinese (very low tumorigenicity cell lines (M or JC strain of MDCK) ) compare to cell lines used by Novartis and others for novel A/H1N1, I cannot find. However, it is clear in this article that by using certain lines and processing them to reduce/eliminate tumorigeicity, this safety issue appears to be addressed.
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