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Method for reducing endotoxin in Moraxella catarrhalis UspA2 protein preparations
M J Fiske1, R A Fredenburg, K R VanDerMeid
1Wyeth-Lederle Vaccines, West Henrietta, NY 14586-9728, USA.
Summary
Reducing endotoxin in the UspA2 protein vaccine candidate from Moraxella catarrhalis is crucial. Zwitterionic detergents effectively removed endotoxin without impacting UspA2
Area of Science:
- Microbiology
- Vaccinology
- Biochemistry
Background:
- Moraxella catarrhalis is a human pathogen, and its UspA2 protein is a promising vaccine candidate.
- Parental vaccine administration requires minimal endotoxin levels.
- Endotoxin was tightly complexed with UspA2, resisting standard dissociation methods.
Purpose of the Study:
- To develop a method for reducing endotoxin levels in UspA2 protein preparations.
- To assess the impact of endotoxin removal on the UspA2 vaccine candidate's immunogenicity.
Main Methods:
- Utilized zwitterionic detergents (Zwittergent 3-12 and 3-14) for endotoxin dissociation.
- Employed ion-exchange and gel filtration chromatography for endotoxin separation.
- Quantified endotoxin reduction using the limulus amoebocyte lysate assay.
Main Results:
- Achieved an approximate 20,000-fold reduction in endotoxin levels.
- Endotoxin removal did not compromise the immunological properties of UspA2.
- Comparable antibody and bactericidal titers were observed in antisera from pre- and post-reduction UspA2.
Conclusions:
- Zwitterionic detergents and chromatography effectively remove endotoxin from UspA2.
- The endotoxin reduction process preserves the UspA2 protein's immunogenicity.
- This method supports the development of a safer UspA2-based vaccine against Moraxella catarrhalis.