Noncovalent Complex Vaccine, Prepared with Detoxified Escherichia coli J5 (RcChemotype) Lipopolysaccharide and Neisseria meningitidis Group B Outer Membrane Protein, Produces Protective Antibodies against Gram-Negative Bacteremia

摘要

Earlier studies showed that purified IgG from sera of rabbits immunized with aboiled Escherichia coli J5 (Rc chemotype) whole cell vaccine protected neutropenic rats against gram-negative bacterial sepsis. In the present study, de-O-acylated J5 lipopolysaccharide (J5 DLPS) as a noncovalent complex with Neisseria meningitidis group B outer membrane protein (GBOMP) elicited anti-J5 LPS antibodies in rabbits. IgG prepared from immune rabbit sera protected neutropenic rats against lethal challenge with Pseudomonas aeruqinosa 12:4:4. Sixteen of 26 rats treated with the postimmune serum IgO were protected compared with none of 20 rats treated with the control rabbit serum IgO (p < .001). In vitro binding studies showed binding of anti-J5 IgG to several gram-negative bacteria. These results indicate that a subunit vaccine made of J5 DLPS as a non-covalent complex with GEOMP may protect against gram-negative bacteremia.