title: Observations on the expression of human papillomavirus major capsid protein in HeLa cells.
abstract: BACKGROUND
  The goal of this study was to identify the nature of the inclusion bodies that have been found in HeLa cells (cervical cancer immortal cell line) by electron microscope and to determine whether the major capsid protein (L1) of human papillomavirus (HPV) can be expressed in HPV-positive uterine cervix cancer cells.
  
  
  METHODS
  HPV L1 protein expression in HeLa cells was detected with anti-HPV L1 multivalent mice monoclonal antibody and rabbit polyclonal anti-HPV L1 antibody by ELISA, light microscope immunohistochemistry, electron microscope immunocytochemistry and Western blotting assays. Reverse transcriptional PCR (RT-PCR) was performed to detect the transcription of L1 mRNA in HeLa cells. The immortalized human keratinocyte HeCat was used as the negative control.
  
  
  RESULTS
  HPV L1 proteins reacted positively in the lysate of HeLa cells by ELISA assays. HRP labeled light microscope immunohistochemistry assay showed that there was a strong HPV L1 positive reaction in HeLa cells. Under the electron microscope, irregular shaped inclusion bodies, assembled by many small and uniform granules, had been observed in the cytoplasm of some HeLa cells. These granules could be labeled by the colloidal gold carried by HPV L1 antibody. The Western blotting assay showed that there was a L1 reaction strap at 80-85 kDa in the HeLa cell lysates, hence demonstrating the existence of HPV18 L1 in HeLa cells. RT-PCR assay showed that the L1 mRNA was transcribed in HeLa cells.
  
  
  CONCLUSIONS
  The inclusion bodies found in the cytoplasm of HeLa cells are composed of HPV18 L1 protein. Since HeLa cell line is a type of cervical cancer cells, this implies that HeLa cells have the ability to express HPV L1 proteins.
authors.affiliation: Tumor Research Institute, China Three Gorges University, Yichang, 443002 Hubei Province People's Republic of China.
authors.forename: Chang-Yi
authors.initials: CY
authors.lastname: Xiao
authors.affiliation: Tumor Research Institute, China Three Gorges University, Yichang, 443002 Hubei Province People's Republic of China.
authors.forename: Bing-Bing
authors.initials: BB
authors.lastname: Fu
authors.affiliation: Department of Gynaecology and Obstetrics, The Second Clinical Medical College of China Three Gorges University, Yichang, 443000 Hubei Province People's Republic of China.
authors.forename: Zhi-Ying
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Biochemistry, College of Science, King Abdulaziz University, Jeddah, 21589 Saudi Arabia.
authors.forename: Gohar
authors.initials: G
authors.lastname: Mushtaq
authors.affiliation: King Fahd Medical Research Center, King Abdulaziz University, Jeddah, 21589 Saudi Arabia ; Enzymoic, 7 Peterlee Place, Hebersham, NSW 2770 Australia.
authors.forename: Mohammad Amjad
authors.initials: MA
authors.lastname: Kamal
authors.affiliation: Tumor Research Institute, China Three Gorges University, Yichang, 443002 Hubei Province People's Republic of China.
authors.forename: Jia-Hua
authors.initials: JH
authors.lastname: Li
authors.affiliation: Tumor Research Institute, China Three Gorges University, Yichang, 443002 Hubei Province People's Republic of China.
authors.forename: Gui-Cheng
authors.initials: GC
authors.lastname: Tang
authors.affiliation: Tumor Research Institute, China Three Gorges University, Yichang, 443002 Hubei Province People's Republic of China.
authors.forename: Shuo-Shuang
authors.initials: SS
authors.lastname: Xiao
keywords: Cervical cancer; Expression; HeLa cells; Human papillomavirus; Major capsid protein