title: Presumable role of outer membrane proteins of Salmonella containing sialylated lipopolysaccharides serovar Ngozi, sv. Isaszeg and subspecies arizonae in determining susceptibility to human serum.
abstract: BACKGROUND
  The O48 group comprises Salmonella bacteria containing sialic acid in the lipopolysaccharide (LPS). Bacteria with sialylated surface structures are described as pathogens that avoid immunological response of the host by making similar their surface antigens to the host's tissues (molecular mimicry). It is known that the smooth-type LPS of Salmonella enterica and outer membrane proteins (OMP) PgtE, PagC and Rck mediate serum resistant phenotype by affecting complement system (C). The aim of this study was to investigate C3 component activation by Salmonella O48 LPS and OMP.
  
  
  RESULTS
  In the present study, we examined C3 component deposition on the three Salmonella O48 strains: S. enterica subspecies enterica serovar Ngozi, S. enterica subsp. enterica sv. Isaszeg, and S. enterica subsp. arizonae containing sialic acid in the O-specific part of LPS. The greatest C3 deposition occurred on Salmonella sv. Isaszeg cells (p < 0.005) as well as on their LPS (low content of sialic acid in LPS) (p < 0.05) after 45 min of incubation in 50% human serum. Weaker C3 deposition ratio on the Salmonella sv. Ngozi (high content of sialic acid in LPS) and Salmonella subsp. arizonae (high content of sialic acid in LPS) cells correlated with the lower C3 activation on their LPS. Immunoblotting revealed that OMP isolated from the tested strains also bound C3 protein fragments.
  
  
  CONCLUSIONS
  We suggest that activation of C3 serum protein is dependent on the sialic acid contents in the LPS as well as on the presence of OMP in the range of molecular masses of 35-48 kDa.
authors.affiliation: Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63-77, 51-148 Wrocław, Poland.
authors.forename: Bożena
authors.initials: B
authors.lastname: Futoma-Kołoch
authors.affiliation: Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63-77, 51-148 Wrocław, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Godlewska
authors.affiliation: Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63-77, 51-148 Wrocław, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Guz-Regner
authors.affiliation: Department of Pathogens' Biology and Immunology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63-77, 51-148 Wrocław, Poland.
authors.forename: Agata
authors.initials: A
authors.lastname: Dorotkiewicz-Jach
authors.affiliation: Regional Centre of Transfusion Medicine and Blood Bank, Czerwonego Krzyża 5, 50-345 Wrocław, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Klausa
authors.affiliation: Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Rybka
authors.affiliation: Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63-77, 51-148 Wrocław, Poland.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Bugla-Płoskońska
keywords: C3; Complement; Lipopolysaccharide; Outer membrane protein; Salmonella O48; Sialic acid