title: Outer membrane protein A (OmpA) of Shigella flexneri 2a, induces protective immune response in a mouse model.
abstract: BACKGROUND
  In our earlier studies 34 kDa outer membrane protein (OMP) of Shigella flexneri 2a has been identified as an efficient immunostimulant.
  
  
  RESULTS
  In the present study MALDI-TOF MS analysis of the purified 34 kDa OMP of Shigella flexneri 2a shows considerable sequence homology (Identity 65%) with the OmpA of S. flexneri 2a. By using the specific primers, the gene of interest has been amplified from S. flexneri 2a (N.Y-962/92) genomic DNA, cloned in pET100/D-TOPO® vector and expressed using induction with isopropyl thiogalactoside (IPTG) for the first time. Immunogenicity and protective efficacy of the recombinant OmpA has been evaluated in an intranasally immunized murine pulmonary model. The recombinant protein induces significantly enhanced protein specific IgG and IgA Abs in both mucosal and systemic compartments and IgA secreting cells in the systemic compartment (spleen). The mice immunized with OmpA have been protected completely from systemic challenge with a lethal dose of virulent S. flexneri 2a. Immunization with the protein causes mild polymorphonuclear neutrophil infiltration in the lung, without inducing the release of large amounts of proinflammatory cytokines.
  
  
  CONCLUSIONS
  These results suggest that the OmpA of S. flexneri 2a can be an efficacious mucosal immunogen inducing protective immune responses. Our findings also demonstrate that antibodies and Th1 immune response may be associated with the marked protective efficacy of immunized mice after intranasal shigellae infection.
authors.affiliation: Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Pore
authors.forename: Nibedita
authors.initials: N
authors.lastname: Mahata
authors.forename: Amit
authors.initials: A
authors.lastname: Pal
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Chakrabarti
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004405:Dysentery, Bacillary / Q000276:immunology* / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D006801:Humans; D007109:Immunity / Q000276:immunology*; D007114:Immunization; D008081:Liposomes / Q000378:metabolism; D008168:Lung / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D020539:Sequence Analysis, Protein; D012763:Shigella flexneri / Q000276:immunology*; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D016207:Cytokines; D008081:Liposomes; D011993:Recombinant Fusion Proteins; C078167:OMPA outer membrane proteins