Vaccine protection assay

摘要

The present invention relates to the field of Serum Bactericidal Activity (SBA) assays for Gram negative bacteria, in particular N. meningitidis. The SBA assay is the most important method for measuring functional activity of serum antibodies against meningococcus. In order to determine whether a subject or a population is seropositive against invasive meningococcus the SBA test should ideally be both sensitive and specific. The inventors have found the standard N. meningitidis serotype A and W SBAs can be significantly improved in this regard.

主权项

1. An assay for determining the Serum Bactericidal Activity (SBA) titre of a serum sample against a Neisseria meningitidis serogroup A where said Neisseria meningitidis serogroup A contains lipooligosaccharide (LOS) antigens, and said serum sample is obtained from a subject who has been immunized with a vaccine composition comprising conjugates of capsular polysaccharides from, Neisseria meningitidis serogroup A but not comprising lipooligosaccharide (LOS) antigens from Neisseria meningitidis serogroup A, said assay comprising the steps of: (a) depleting said serum sample of antibodies against lipooligosaccharide (LOS) epitopes from an LOS immunotypes of a reference strain of said Neisseria meningitidis serogroup A, where said LOS epitopes are from Los immunotypes from the group consisting of L1, L2, L3, L4, L5, L5, L6, L7, L8, L9, L10, L11, and L12 and then (b) determining the SBA titre of said serum sample against the reference strain of said Neisseria meningitidis serogroup A.