Reactivity and protective capacity of a polyclonal antiserum derived from mice immunized with antibiotic exposed Escherichia coli.
The murine immune response to Escherichia coli O6:K-alone or pre-exposed to 0.1 x MIC of aztreonam was investigated. Relative to mice immunized with untreated bacteria, mice immunized with antibiotic-treated microorganisms presented a significantly enhanced protection towards a challenge of 100 x LD50 of viable E. coli O6:K-. Previous injection of 0.1 mL of serum drawn from mice immunized with treated and untreated bacteria protected non-immunized mice towards a challenge of 10 x LD50 of viable E. coli O6:K--. Serum from mice immunized with treated bacteria also protected non-immunized mice towards a lethal challenge of E. coli O111. The antiserum contained high titre of IgG antibodies that cross-reacted with lipopolysaccharide isolated from smooth and rough Gram-negative bacteria. Immunoblotting showed additional bands of reactivity to the untreated E. coli O6:K-. Immunization with antibiotic-treated bacteria led to the production of type specific and cross reactive antibodies that protected animals against viable homologous and heterologous lethal challenges.
Raponi
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II Chair of Microbiology, Faculty of Medicine, La Sapienza University of Rome, Italy.
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Lorino
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Nazzari
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Gaeta
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Mancini
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Filadoro
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D000818:Animals; D001398:Aztreonam / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000276:immunology; D004927:Escherichia coli Infections / Q000517:prevention & control; D007106:Immune Sera / Q000276:immunology*; D007116:Immunization, Passive; D051379:Mice; D011292:Premedication
D007106:Immune Sera; D001398:Aztreonam