Identification of novel Neisseria meningitidis serogroup B (MenB) vaccine candidates.
Whilst the development and licensing of the Bexsero MenB vaccine is an important advance, there are still questions to be resolved as to how good it will be. For example, it is only predicted to be effective against 73 - 88% of UK strains of MenB bacteria. It is therefore important and widely acknowledged that the scientific and medical community continue MenB vaccine research. We all strive for a universal vaccine that will eradicate MenB disease and this project will contribute to that urgently needed goal.
What the research team did
The researchers planned to use a novel approach to find further vaccine candidates that will either help to improve, or be an alternative to the currently available MenB vaccine Bexsero.
Blood will be taken from patients who have had MenB disease and single cells that produce antibodies will be identified and isolated. The genes that make antibodies are cloned so that large amounts of individual antibodies can be produced in the laboratory. Each individual antibody will be tested for its ability to bind and kill MenB cells that are known to cause disease in the UK. The protein molecules on the surface of MenB which are recognised by “killing” antibodies will be found. Such MenB proteins are highly promising vaccine candidates.
This method has not been used on MenB before and so is likely to find completely novel vaccine candidates that could be used to improve protection against MenB disease.
Summary and impact of results
A blood sample taken from a patient who was recovering from MenB disease was used to produce 139 different antibodies. Eight of these antibodies recognised, and bound to, MenB strains, including those that are known to cause disease in the UK and those that are not covered by Bexsero®. Of these eight antibodies, three were able to kill MenB stains and interestingly, none of these killer antibodies recognised any of the proteins in the Bexsero® vaccine. This means that there are other MenB proteins that could be new vaccine candidates.
The researchers have been able to narrow down the identity of these proteins to a small number of possibilities and the manufacturer of the Bexsero® vaccine has now expressed interest in taking this work further. The next stage of this work will be to determine whether these new proteins can actually be used in a vaccine.
This research has shown that this approach can be used to identify potential new vaccine antigens, not only for meningococcal disease, but also for other infections such as pneumococcal disease.