Ultrafiltration for preparing outer membrane vesicles

Abstract

In place of a step of centrifugation during preparation of outer membrane vesicles (OMVs) from bacteria, the invention utilises ultrafiltration. This allows much larger amounts of OMV-containing supernatant to be processed in a much shorter time. Thus the invention provides a process for preparing bacterial OMVs, comprising a step of ultrafiltration. The ultrafiltration step is performed on an aqueous suspension of OMVs after they have been prepared from bacteria and the OMVs remain in suspension after the filtration step. The invention is particularly useful for preparing OMVs from Neisseria meningitidis.

1 - 16 . (canceled) 
     
     
         17 . Bacterial OMVs obtainable by a process comprising a step of ultrafiltration. 
     
     
         18 . A pharmaceutical composition comprising the OMVs of  claim 17  and a pharmaceutically acceptable carrier. 
     
     
         19 . The composition of  claim 18 , comprising an aluminium hydroxide adjuvant and a histidine buffer. 
     
     
         20 . The composition of  claim 18 , wherein the composition is substantially free from whole bacteria. 
     
     
         21 . A vial containing the composition of  claim 18 . 
     
     
         22 . A syringe containing the composition of  claim 18 . 
     
     
         23 . A method for raising an immune response in a patient, comprising administering an immunogenic dose of the composition of  claim 18 .