title: Entamoeba histolytica acetyl-CoA synthetase: biomarker of acute amoebic liver abscess.
abstract: OBJECTIVE
  To characterize the Entamoeba histolytica (E. histolytica) antigen(s) recognized by moribound amoebic liver abscess hamsters.
  
  
  METHODS
  Crude soluble antigen of E. histolytica was probed with sera of moribund hamsters in 1D- and 2D-Western blot analyses. The antigenic protein was then sent for tandem mass spectrometry analysis. The corresponding gene was cloned and expressed in Escherichia coli BL21-AI to produce the recombinant E. histolytica ADP-forming acetyl-CoA synthetase (EhACS) protein. A customised ELISA was developed to evaluate the sensitivity and specificity of the recombinant protein.
  
  
  RESULTS
  A ∼75 kDa protein band with a pI value of 5.91-6.5 was found to be antigenic; and not detected by sera of hamsters in the control group. Tandem mass spectrometry analysis revealed the protein to be the 77 kDa E. histolytica ADP-forming acetyl-CoA synthetase (EhACS). The customised ELISA results revealed 100% sensitivity and 100% specificity when tested against infected (n=31) and control group hamsters (n=5) serum samples, respectively.
  
  
  CONCLUSIONS
  This finding suggested the significant role of EhACS as a biomarker for moribund hamsters with acute amoebic liver abscess (ALA) infection. It is deemed pertinent that future studies explore the potential roles of EhACS in better understanding the pathogenesis of ALA; and in the development of vaccine and diagnostic tests to control ALA in human populations.
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Lim Boon
authors.initials: LB
authors.lastname: Huat
authors.affiliation: Departmento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F., Mexico.
authors.forename: Alfonso Olivos
authors.initials: AO
authors.lastname: Garcia
authors.affiliation: Department of Medicine, Allianze University College of Medical Sciences, Pulau Pinang, Malaysia.
authors.forename: Tan Zi
authors.initials: TZ
authors.lastname: Ning
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Wong Weng
authors.initials: WW
authors.lastname: Kin
authors.affiliation: Institute for Research in Molecular Medicine, 11800 Universiti Sains Malaysia, Penang, Malaysia.
authors.forename: Rahmah
authors.initials: R
authors.lastname: Noordin
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Siti Shafiqah Anaqi
authors.initials: SS
authors.lastname: Azham
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Lee Zhi
authors.initials: LZ
authors.lastname: Jie
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Guee Cher
authors.initials: GC
authors.lastname: Ching
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Foo Phiaw
authors.initials: FP
authors.lastname: Chong
authors.affiliation: Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Pim Chau
authors.initials: PC
authors.lastname: Dam
keywords: Acetyl-CoA synthetase; Amoebic liver abscess; Biomarker; Entamoeba histolytica; Recombinant EhACS; Western blot