(image source) 

Aetiology and epidemiology

Meninigococcal meninigits and septicemia are devastating diseases caused by Neissieria meningitidis. Although infants and young children are the most susceptible to the disease, adults are also affected but with less incidence. N.meningitidis is a gram negative capsulated bacterium that has been classified into five serogroups (A, B, C, Y, W135)  based on their polysaccharide capsule.

The challenge

Over forty years, developing a vaccine against this dangerous bacterium proceeded with little success. In 1960, the purified polysaccharide antigens were used to develop a vaccine against four groups (A, C, Y, W135) . Unfortunately, this vaccine was highly effective in adults but didn’t give protection to young infants and children who represent the age group most susceptible to the disease. Another challenge is that this vaccine didn’t show success against serogroup B (known as:MenB).

More attempts to overcome the new challenge

Using capsular polysaccharide antigen, as a vaccine against MenB, wasn’t a very good idea. This is due to the fact that MenB capsular polysaccharide is highly similar (nearly identical) to N-acetyl neuraminic acid which is widely distributed in human tissue and that means it is a self antigen. The new vaccine was poorly immunogenic (and thus provide poor protection) and also it might elicit auto-antibodies.

As scientists never give up, they switched into the new trend in vaccinology: Reverse vaccinology. Due to the formerly mentioned, N.meningitidis was expected to be a very promising candidate for reverse vaccinology.

RV provides help

Using in silico technique (computational biology), the genome sequence was fed into a computer, 570 proteins of the bacterium surface were predicted. Going for more refinement, only 350 of these proteins were successfully expressed in E.coli and and used to immunise mice. The sera assays allowed the identification of certain proteins that elicit bactericidal antibodies and surprisingly, were conservative among different strains and this meets the criteria for a good vaccine.

Going forward

As research is proceeding to deprive our pathogen from enjoying its life inside our bodies, this work suggested further research of other pathogens such as: Streptococcus pneumoniae, Chlamydia pneumoniae, Bascillus anthracis, T.B and group B Streptococcus. 


A universal vaccine against serogroup B meningococcus.

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5 Responses to “Thanks to RV:A vaccine against N.meningitidis is not a problem anymore”
  1. This is so specific. But lots of work to do, sequence/ identify/ predict/ clone/ try what works. But eventually, it’s a real breakthrough. It’s still through painful injection, right?! Kids won’t like that part. The topic is very well-organized. Thank you.

  2. the image show how much vaccination is painful and i meant it.The pain of vaccination is more dull than getting infection of meninigitis, isn’t it?

  3. thanks for the information rose
    as you were saying, the injection is painful..maybe scientists can come up with an inhalation device instead just like the insulin inhaler, but I am not sure if the protein particles would be small enough to penetrate the alveolar blood capillaries

  4. I don’t think a vaccine being protein in nature will face a problem in inhalation formulation as insulin which is 51 amino acids is successfully formulated as inhalation.
    But vaccination is usually done once or just few times so the pain problem is not that real problem which will make us search for ulternative routes of administration. For insulin it is injected daily so the pain is a major problem.
    Generally speaking, the route of administraion is not only determined by the possibility of good absorption but by the whole kinetic profile of the drug and also by the intrinsic properties of the drug.

    Anyway, there are some releases about inhalation vaccines against (T.B, measles, Anthrax) but I don’t think there is any against N.meningitidis.
    Read more in these links:
    Anthrax nasal vacciantion
    Science Direct

  5. I can tell the girl in the pic likes getting shots, but they will appretiate it later on in life

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