title: Cloning, Expression and Purification ofL. DonovaniSpecific Antigen for Serodiagnosis of Visceral Leishmaniasis.
abstract: BACKGROUND
  Rapid diagnostic test using rk39 antigen is widely used for visceral leishmaniasis. However it detects anti-rk39 antibodies in 20-32% of endemic healthy individuals. In search for a better biomarker of infection, we identified a protein of molecular weight 70 kDa (BHUP1), specifically recognized by sera of visceral leishmaniasis (VL) patients.
  
  
  METHODS
  The protein was cloned as His-tagged fusion protein and purified. We evaluated the sensitivity and specificity of this protein in an enzyme linked immunosorbant assay (ELISA) format in comparison to the rk39 antigen using sera collected from various groups of individuals.
  
  
  RESULTS
  The sensitivity of rBHUP1 was 96.5% compared to 98.8% with rk39. For healthy controls from non endemic and endemic regions, the specificity of rBHUP1 was 100% and 95.6% compared to 100% and 84.9% for rk39, respectively. For other infectious diseases such as malaria, tuberculosis, viral fever, etc., specificity of rBHUP1 was as low as 74.5% when compared to 94% of rk39. At six month and one year follow-up, 74% and 22.5% patients tested positive with rBHUP1, respectively, compared to 97% and 77.4% with rk39 antigen.
  
  
  CONCLUSIONS
  Though the high sensitivity and specificity of rBHUP1 antigen for VL and healthy controls would have made it a good diagnostic biomarkers, however, its non-specific reaction with other infectious diseases limit its utility.
authors.affiliation: Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, U.P, India.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, U.P, India.
authors.forename: Puja
authors.initials: P
authors.lastname: Tiwary
authors.affiliation: Division of Parasitology, Central Drug Research Institute, Lucknow, U.P, India.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Dube
authors.affiliation: Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, U.P, India.
authors.forename: Jaya
authors.initials: J
authors.lastname: Chakravarty
authors.affiliation: Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, U.P, India.
authors.forename: Madhukar
authors.initials: M
authors.lastname: Rai
authors.affiliation: Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, U.P, India.
authors.forename: Shyam
authors.initials: S
authors.lastname: Sundar
keywords: ELISA; Visceral leishmaniasis; rBHUP1; rk39