400 likes | 640 Views
The quality control of cell lines and the prevention , detection, and cure of contamination. Obtaining the basic materials Importance of cell culture collections: 1. well characterized, microbe free seed stock 2. prevention of cross-contamination.
E N D
The quality control of cell lines and the prevention, detection, and cure of contamination
Obtaining the basic materials Importance of cell culture collections: 1. well characterized, microbe free seed stock 2. prevention of cross-contamination
Resource Center 1.ATCC( American Type Culture Collection Over 3200 cell lines and hybridoma from 75 species ATCC.com 2 .National Institute of general Medical Science ( NIGM) 5270 cell cultures and 275 DNA samples mainly derived from patients with genetic and chromosomal abnormalities 3.European collection of animal cell culture ( ECACC) 1200 cell lines and hybridoma 7000 human genetic and chromosome abnormality cell lines
4.Riken gene Bank( Japan) 300 cell lines and hybridoma 5.Department of Human and Animal Cell Culture ( Germany) 100 cell lines and hybridoma
Quarantine and initial handling of cell lines • cultures should be handled in class II safety cabinet • cultures should be handled in a Quarantine laboratory separate from main tissue culture area • a token freeze should be made as soon a possible • initial characterization and microbial control should be made
NEW CELL LINES expand TOKEN FREEZEquality control QUARANTINE LABORATORY ---------------------------------------------------------------------- MAIN CULTURE SUIT expand culture MASTER BANK quality control expand one ampoule WORKING BANK( 40-100 AMPOULE) quality control expand one ampoule TERMINATION OF CULTURES
Source of contamination • Operators technique inadequately trained personal Environment poor laboratory condition • Use and maintenance of laminar flow • Humid incubator • Cold stores • Sterile materials • Imported materials and biopsies • Quarantine non-quality controlled cell lines
Monitoring contamination Check by eyes and microscope • Clean hood and every thing if contamination is suspected • Record nature of contamination • Check stock solution , sterilization procedure if similar contamination occur • Do not try to decontaminate unless the contamination is irreversible
Microbial Contamination • Sudden change of pH decrease in bact contamination, increase in fungal contamination • Cloudiness in the medium • Granular appearance between cells( ~x100) bacterial contamination
Types of Microbial Contamination Bacteria , Fungi Mold, mycoplasma, prptozoa bacteria yeast
mycoplasma mold Mycoplasma on culture cell
2.testing for bacteria, yeast, and other fungi may be detected by turbidity of the medium pH change methods: Thioglycollate medium enrichment medium used in qualitative procedures for the sterility test and for the isolation and cultivation of aerobes, anaerobes and microaerophiles e.g. sodium thioglycolate: comsume O2 and allow growth of anaerobes microbes
Strict aerobe aerotolerant anaerobe strict anaerobe faculative microaerophile http://www.youtube.com/watch?feature=player_embedded&v=x9bMS1G1myw
Common sources for microbial contamination Bacteria Sources clothing,skin,hair,aerosol( sneezing pipetting),insecure caps on media and culture flask air current humidified incubator purified water insects contaminated cell line plants
Fungi( excluding yeast) fruit damp wood or other cellulose products humidified incubator Yeast bread humidified incubator operators Mycoplasma contaminated cell lines serum medium operator
Detection of Bacteria and Fungi in Cell Culture http://www.youtube.com/watch?v=_fAVPMbkm78
Mycoplasma • affect the rate of cell growth induce morphological change cause chromosome aberration influence amino acid and nucleic metabolism induce cell transformation
Fluorescence stainning of mycoplasma Hoechst 33258 DNA staining method PCR detection of mycoplasma Two step PCR Universal primer amplify region between major region gene ( 16S and 23S rRNA) amplify spacer region of contaminated mycoplasma
100 bp ladder Water control Positive sample Negative sample Positive control Positive control + internal control Negative sample+ internal control Positive sample + internal control
Other methods of detecting mycoplasma • Mycrobial culture 2. Molecular hybridization 3. 3H thymidine incorporation 3H labeled s.s DNA probe( homologous with mycoplasma) 4. mycoplasma detection kit ( enzyme immuno assay ) 5. Myco-tech kit: cells coculture with 6-ethylpurine deoxyribose toxic compound forms cell dies
Virus contamination a) virus sources: tissue derived viral contamination depend upon: species of origin the tissue taken the clinical history of the animal and patient e.g.HBV( 0.2—0.5% of blood donor were infected) some virus which can occur in humans exp. . Herpes simplex virus-1 Herpes simplex virus-2 human cytomegalovirus Epstein-barr virus hepatitis B, Hepatitis C Human herpes virus-6 HIV-1,HIV-2 Human T-cell lymphotropic virus-1 Human T-cell lymphotropic virus-2……………………….
b)Serum derived viral contamination e.g. Bovine Viral Diarrhoed Virus infectious bovine rhinotracheitis virus Parainfluenza may be detected by PCR or fluorescence methods
c) methods of detection cocultivation cell extract of the tested cell lines cell extract was added into sensitive cell line( BHK21, WI 38, HeLa, Vero, MDCK, JM, H9, fresh T cell) electron microscope In vivo methods cell culture assay for murine retrovirus example: Murine leukemia Virus( MuLV) Characters: i) ectropic( infect only rodent cells) ii)xenotropic( infect only cells other than rodent) iii)amphotropic
reverse transcriptase assay for retrovirus detection precipitate virus particles with PEG R.T activity assay PCR method for detection of BVDV and other virus
5.Bovine Spongiform encephalopathy 1986, found in contaminated feed stuffs of cattles 6.Elimination of contamination a. discard contaminated culture b.find the source of contamination c.eliminate source of contamination fumigate the whole lab swab cell surfaces and equipment use of antibiotics using 10-14 days for at least 3 passages
Antibiotics commonly used in elimination of microbial contamination Antibiotics working concentration active against AmphotrricinB 2.5mg/L yeast and other fungi Ampicillin 2.5mg/L bacteria(Gp,Gn) Cephalothin 100mg/L bacteria(Gp,Gn) Ciprofloxacin 10-40mg/L mycoplasma Gentamycin 50mg/L bacteria(Gp,Gn), mycoplasma Kanamycin 100mg/L bacteria(Gp,Gn), yeast mycoplasma removal agent 0.5mg/L mycoplasma Neomycin 50mg/L bacteria(Gp,Gn) Nystatin 50mg/L yeast and other fungi Penicillin-G 100000U/L bacteria(Gp) PolymyxinB 50mg/L bacteria(Gn) Streptomycin sulphate 100mg/L bacteria(Gp,Gn) Tetracycline 10mg/L bacteria(Gp,Gn)
Authentication To confirm the identity and origin species of the cell stocks 1. Isozyme analysis polymorphic enzyme variants catalyze the same reaction but have different electrophoretic mobility
G6PD:Glucose - 6 – Phosphate Dehydrogenase LDH:Lactate Dehydrogenase NP:Nucleoside Phosphorylase AST:Aspartate Aminotransferase
2.Cytogenic analysis To establish the common chromosome complement or karyotype of a species or cell lines Giemsa banding( G banding, pH 6.8 giemsa), G11 banding( pH 11 giemsa stain) , Quinacrine ( Q) banding
3.DNA fingerprinting Southern blotting hybridization
Southern blotting hybridization DNA extraction form sample DNA cut into fragments by restriction enzyme, separation by electrophoresis transfer DNA transfer to nylon membrane Application of with radiolabelled probe Develpoment of x-ray film
http://local.testing4dna.com/Local-Cell-Line-Authentication.htmlhttp://local.testing4dna.com/Local-Cell-Line-Authentication.html
Comparison of the uses of the different cell authentification methods available Application DNA finger printing cytogenic Isozyme analysis analysis species determination individual identification detection of cell line variation regulatory authority recognition
Information required for regulatory approval 1. History and genealogy of the cell line 2. Records and storage information on master and working cell banks 3.Culture requirements 4. Growth characteristics 5. Production and testing facilities 6. Quality control test: karyology,isozyme analysis,DNA fingerprinting,virus testing, retrovirus status, test for contaminated DNA, purification procedure/validation date characterization of products