To investigate the relationship between the morphologic changes and the expression of keratin and proto-oncogene induced by Beta-propiolactone (BPL), we assessed on the expression of keratins (K8, K10, K13) and proto-oncogenes (c-fos, c-jun, c-myc) in human HaCaT cell line. The cells were treated with 0, 0.1, 1 microgram/ml BPL for 2 or 6 hours. Morphologic studies revealed that BPL changed the cells into fibrocyte-shaped, caused highly lobulated nuclei and reduced desmosomes in their number. Findings of immunofluorescence and Northern blotting indicated that BPL consistently decrease expression of K10 representing a normal differentiation marker of keratinocytes, while increasing expression of K8 and K13 associated with a pathologic differentiation. This reagent also up-regulated expression of c-fos and c-jun, and down-regulated expression of c-myc. Together with staining for each keratin or proto-oncogene and DNA content in flow cytometry, BPL increased K8 expression dramatically at S-G2-M phase. The induction of c-Fos at S-G2-M phase appeared within 2 hours, and c-Jun gradually occurred. However, c-Myc was inhibited regardless of phases of cell cycle. In conclusion, these changes caused by BPL demonstrate a close relationship between the morphologic evidence and the altered expression of each keratin and proto-oncogene.
Blotting, Northern ; Cell Cycle ; Cell Line ; Desmosomes ; DNA ; Flow Cytometry ; Fluorescent Antibody Technique ; Humans ; Keratinocytes ; Propiolactone* ; Proto-Oncogenes*

OBJECTIVETo study the method for cultivation and inactivation of SARS-CoV.

METHODSIn order to choose the sensitive cell strain and the best infection dose of the virus, Vero, Vero-E6 and 2BS cell lines were infected with SARS-CoV. The cultivation temperature was selected among 25 degrees C, 33 degrees C and 37 degrees C. The best inactivating time and effect were observed with beta-propiolactone whose concentration ranged from 1:2000 to 1:20,000 at room temperature.

RESULTSVero and Vero-E6 cell lines were sensitive to SARS-CoV. The cytopathic changes of the cells were 75% at 37 degrees C in 5 percent CO2 incubator after infection. SARS-CoV was inactivated completely in beta-propiolactone (1:4000). The toxicity of beta-propiolactone was hydrolyzed completely when the inactivated virus was cultured for 16 hours at 2 degrees C, 8 degrees C and in water bath for 2 hours at 37 degrees C.

CONCLUSIONThe titer of SARS-CoV was the highest when it was cultured in Vero or Vero-E6 cells for 72 hours at 37 degrees C in 5 percent CO2 incubator. SARS-CoV was inactivated completely in beta-propiolactone when its concentration was 1:4000 and the interaction time was 1 hour.

Animals ; Cercopithecus aethiops ; Dose-Response Relationship, Drug ; Propiolactone ; pharmacology ; SARS Virus ; drug effects ; growth & development ; Temperature ; Time Factors ; Vero Cells ; Virus Inactivation ; drug effects