title: Identification and purification of antigenic 34 kDa outer membrane protein of Salmonella typhi.
abstract: BACKGROUND
  Salmonella Typhi is a pathogenic bacterium that causes a number of infectious diseases such as gastroenteritis and typhoid fever. In this study, an antigenic (34 kDa) protein was identified, purified, and characterized from outer membrane of Salmonella typhi.
  
  
  METHODS
  Immunoblot analysis was used to screen antigenic proteins from outer membrane of Salmonella Typhi. Proteins from outer membrane were isolated and resolved on SDS-PAGE. In immunoblot analysis, four proteins with the following molecular weights of 60 kDa, 54 kDa, 34 kDa, and 26 kDa were identified as highly antigenic against the serum of patients suffering from typhoid fever. One of these outer membrane proteins, with a molecular mass of 34 kDa, was selected for this study. The 34 kDa protein was purified and characterized by a combination of anion exchange chromatography and gel permeation chromatography. The molecular weight of 34 kDa was determined using SDS-PAGE electrophoresis. The antigenic nature of the purified 34 kDa protein was determined by ELISA against serum proteins of patients suffering from typhoid fever and finally confirmed by immunoblot analysis. Antisera against the purified 34 kDa outer membrane protein of Salmonella typhi was produced and was used to recognize the epitope on the surface of an intact Salmonella typhi bacterium.
  
  
  RESULTS
  The antigenic 34 kDa protein from the outer membrane of Salmonella typhi was identified, purified and characterized. The antigenecity of purified protein was confirmed by using antibodies present in serum of patient suffering from typhoid fever. It was also observed that antibody against 34 kDa outer membrane protein recognizes intact Salmonella typhi cells.
  
  
  CONCLUSIONS
  It is established from the study that 34 kDa protein is antigenic in nature and antibody against this protein can also recognize epitopes on intact Salmonella typhi cells. Furthermore, this protein can be a good source material to produce vaccine against typhoid fever.
authors.affiliation: Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan. shahbazaslam123@yahoo.com
authors.forename: Muhammad Shahbaz
authors.initials: MS
authors.lastname: Aslam
authors.forename: Mohsina
authors.initials: M
authors.lastname: Akhter
authors.forename: Raheema
authors.initials: R
authors.lastname: Rasheed
authors.forename: Zahoor Qadir
authors.initials: ZQ
authors.lastname: Samra
authors.forename: Iram
authors.initials: I
authors.lastname: Gull
authors.forename: Muhammad Amin
authors.initials: MA
authors.lastname: Athar
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting; D008970:Molecular Weight; D012486:Salmonella typhimurium / Q000276:immunology / Q000302:isolation & purification*; D014435:Typhoid Fever / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins