Serological characterization of the core region of lipopolysaccharides of rough Proteus sp. strains.
BACKGROUND
Both smooth and rough Proteus sp. strains can be found. The latter are characterized by their lack of an O-polysaccharide chain in the lipopolysaccharide (LPS) molecule, which makes them suitable for obtaining anti-core sera. Using this kind of material enables identifying fragments of the Proteus LPS core region that might be involved in cross-reactions. To date only a few similar epitopes have been established for the genus Proteus.


METHODS
Polyclonal rabbit antisera directed against three rough strains of Proteus sp. were tested by enzyme-linked immunosorbent assay (ELISA) with a set of LPSs. The reactivity of the selected cross-reactive and homologous systems was checked by the Western blot technique and by a passive immunohemolysis assay preceded by the absorption of each antiserum with appropriate cross-reactive and homologous alkalized LPSs.


RESULTS
On the basis of the ELISA results, 19 cross-reactive antigens were selected among which both smooth and rough LPS forms were found. All the observed reactions involved the core region of the LPS. Using the antisera absorbed with the appropriate LPSs allowed identification of four groups of antigens with serologically identical core regions.


CONCLUSIONS
Comparing the results of the serological studies with the known chemical structures of the core regions of the LPSs used enabled the identification of a few core oligosaccharide fragments probably involved in the observed cross-reactions. All were located in the most distal part of LPS core region, which made them more easily recognized by specific antibodies.
Palusiak
Agata
A
Department of General Microbiology, Institute of Microbiology, Biotechnology and Immunology, University of Łódź, Banacha 12/16, 90-237 Łódź, Poland. agatapal@biol.uni.lodz.pl
Sidorczyk
Zygmunt
Z
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D007120:Immunochemistry; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D011511:Proteus / Q000276:immunology*; D011512:Proteus Infections / Q000175:diagnosis / Q000276:immunology*; D011817:Rabbits; D012698:Serologic Tests / Q000379:methods
D000906:Antibodies; D000942:Antigens, Bacterial; D008070:Lipopolysaccharides; D010446:Peptide Fragments; C430212:lipopolysaccharide, Proteus