title: Immunoprotectivity of Salmonella enterica serovar Enteritidis virulence protein, InvH, against Salmonella typhi.
abstract: OBJECTIVE
  Typhoid fever is a dreadful disease of a major threat to public health in developing countries. Vaccination with bacterial immunodominant components such as surface proteins may prove as a potent alternative to live attenuated vaccines. InvH, an important part of needle complex in type three secretion system (TTSS) plays important role in efficient bacterial adherence and entry into epithelial cells.
  
  
  METHODS
  In this work we used a 15 kDa recombinant InvH protein of Salmonella enteric serovar Enteritidis to provoke antibody production in mouse. The mice were immunized by recombinant InvH and challenged with Salmonella typhi. Histopathology of spleen and liver were studied.
  
  
  RESULTS
  The immunized mice showed a significant rise of antibody after the second booster. The immunization induced protection against high doses of S. typhi. The bacterial challenge with sera showed significant protection against challenge dose of 2×10(9) CFU. Immunized sera reacted with S. typhi markedly. Immunoreaction of bacterially infected sera and InvH protein was significantly higher than the control group. Bacterial loads of S. typhi in spleen was more than liver. Decreased bacterial load was evident in immunized mice after 7 days. Histological examination of the liver showed the immunized mice liver remained unaffected.
  
  
  CONCLUSIONS
  Efficacy of the virulence protein, InvH, in inhibition of this phenomenon by active immunization was shown here. It may be concluded that InvH, as an antigen, can develop protection against S. typhi infections. InvH may be exploited in protective measures as well as a diagnostic tool in Salmonella infections.
authors.affiliation: Department of Biology, Shahed University, Tehran, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Dehghani
authors.affiliation: Department of Biology, and Molecular Microbiology Research Center, Shahed University, Tehran, Iran.
authors.forename: Iraj
authors.initials: I
authors.lastname: Rasooli
authors.affiliation: Department of Pathology, School of Medicine, Shahed University, Tehran, Iran.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Jalali-Nadoushan
authors.affiliation: Department of Microbiology, School of Medicine, and Molecular Microbiology Research Center, Shahed University, Tehran, Iran.
authors.forename: Parviz
authors.initials: P
authors.lastname: Owlia
authors.affiliation: School of Medicine, Shahed University, Tehran, Iran.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Rasooli
keywords: Immunogenicity; InvH; Salmonella typhi; Vaccine