In vitro potency assay for protein-based meningococcal vaccines
The invention uses ELISA or similar assays for analysing a meningococcal vaccine. The assay uses antibodies which bind to meningococcal proteins within the vaccine, and in particular monoclonal antibodies which are bactericidal for meningococcus and/or which recognise conformational epitopes within the meningococcal proteins. By performing the assay on a series of dilutions of a test vaccine, and by comparing the results with those obtained using a reference vaccine of known potency, it is possible to determine the relative potency of the test vaccine. This value can be used as a parameter for determining whether a manufactured batch of a vaccine is suitable for release to the public, or whether it has experienced a production failure and so should not be used.
1. A method of assessing relative potency in vitro of a batch of vaccine or a bulk vaccine comprising the steps of:
(i) taking a sample from the batch of vaccine or the bulk vaccine comprising a meningococcal protein immunogen, wherein the meningococcal protein immunogen is factor H binding protein (fHbp);
(ii) contacting the sample with a monoclonal antibody wherein the monoclonal antibody
(a) V L region has the amino acid sequence of SEQ ID NO: 21 and V H region has the amino acid sequence of SEQ ID NO: 22,
(b) V L region has the amino acid sequence of SEQ ID NO: 23 and V H region has the amino acid sequence of SEQ ID NO: 24,
(c) V L region has the amino acid sequence of SEQ ID NO: 25 and V H region has the amino acid sequence of SEQ ID NO: 26, or
(d) V L region has the amino acid sequence of SEQ ID NO: 27 and V H region has the amino acid sequence of SEQ ID NO: 28; then
(iii) measuring immunospecific binding of the meningococcal protein immunogen to the monoclonal antibody; then
(iv) comparing the measurement from step (iii) to a measurement obtained by
(1) having contacted a standard vaccine sample comprising the meningococcal protein immunogen of known in vivo potency with the monoclonal antibody; then
(2) having measured binding of the meningococcal protein immunogen in the standard vaccine sample to the monoclonal antibody
to determine the potency of the batch of vaccine or the bulk vaccine relative to the potency of the standard vaccine sample.
2. The method of claim 1 , wherein the measuring the binding comprises quantitatively detecting the meningococcal protein immunogen in the sample.
3. The method of claim 1 , wherein the binding is measured by competitive ELISA.
4. The method of claim 3 , wherein the competitive ELISA comprises contacting the sample in the presence of a competitor antigen attached to a solid surface, wherein the competitor antigen binds to the monoclonal antibody.
5. The method of claim 1 , further comprising contacting the monoclonal antibody with a secondary antibody labelled with an enzyme.
6. The method of claim 1 , wherein the contacting is performed in a microwell plate.
7. The method of claim 1 , wherein the sample further comprises meningococcal Neisserial Heparin Binding Antigen (NHBA) or meningococcal Neisserial adhesin A (NadA).
8. The binding assay of claim 1 , wherein the sample further comprises a meningococcal vesicle.
9. The method of claim 1 , wherein the meningococcal protein immunogen is adsorbed to an aluminum salt adjuvant.
10. The method of claim 1 , wherein the monoclonal antibody is the only monoclonal antibody used in step (ii).
11. The method of claim 1 , wherein the monoclonal antibody is a murine monoclonal IgG antibody.