GERMLINE TARGETING APPROACH

Subject: Science & tech

Context: A new vaccine candidate meets the effectiveness target set by WHO for combating the disease.

Concept:

IAVI and Scripps Research Institute had announced encouraging results from a small trial of a vaccine against HIV that is based on the ‘germline targeting’ approach.
Now, a vaccine with 77% effectiveness over one year could help deliver the world, especially developing nations, from a dreaded child-killer: malaria.

Germline Targeting Approach

The germline-targeting approach is meant to launch the production of the desired bnAb by stimulating the right antibody-producing cells. Antibodies are produced by immune cells called B cells, which start out in a “naïve” or “germline” state.
A large repertoire of these germline B cells circulates in the blood and other tissues.
In a viral infection–or after immunization with a vaccine that mimics an infecting virus–some germline B cells will bind at least weakly to structures on the surface of the virus.
That will stimulate the cells to begin a weeks-long maturation process, in which the antibodies continuously improve in their ability to bind to the surface, thereby neutralizing the virus.
The germline-targeting strategy for an HIV vaccine aims to stimulate the small number of germline B cells that are capable of maturing into cells that make bnAbs.

R 21 VACCINE

The R21 vaccine candidate is produced by expressing recombinant HBsAg virus-like particles in Hansenulapolymorpha, comprising the central repeat and the C-terminus of the circumsporozoite protein (CSP) fused to the N-terminal end of HBsAg10.
R21 was created by the University of Oxford, located in England.
R21 was mixed immediately before administration with Matrix-M™, a saponin-based vaccine adjuvant produced by Novavax AB, Uppsala, Sweden.
The Matrix-M component of the malaria vaccine will be manufactured and supplied to SII by Novavax.
Under Novavax’s agreement with Serum Institute, SII has rights to use Matrix-M in the vaccine in regions where the disease is endemic and will pay Novavax royalties on its market sales of the vaccine.