New Modular Vaccine Design Combines Existing Vaccine Technologies

A new method of vaccine design, called the Multiple Antigen Presentation System (MAPS), may result in vaccines that bring together the benefits of whole-cell and acellular or defined subunit vaccination. The method was pioneered by researchers at Boston Children's Hospital. The method permits rapid construction of new vaccines that activate multiple arms of the immune system simultaneously against one or more pathogens, generating robust immune protection with a lower risk of adverse effects, according to a Boston Children’s Hospital.

The vaccines available fall into two broad categories: whole-cell vaccines, which rely on weakened or killed bacteria or viruses; and acellular or subunit vaccines, which include a limited number of antigens—portions of a pathogen that trigger an immune response. Both approaches have advantages and disadvantages.

The MAPS method may allow vaccine developers to take a middle ground, where they can link multiple protein and polysaccharide (sugar) antigens from one or more pathogens together in a modular fashion, much as one would connect Lego blocks.

The resulting complex—which resembles a scaffold of polysaccharides studded with proteins—can stimulate both antibody and T-cell responses simultaneously much like whole-cell vaccines, resulting in stronger immunity to the source pathogen(s). However, because the composition of a MAPS vaccine is well defined and based on the use of isolated antigens, the risk of side effects may be greatly reduced.

The system relies on the interactions of two compounds, biotin and rhizavidin, rather than covalent binding as is used in most of the current conjugate vaccines. To build a MAPS vaccine, biotin is bound to the polysaccharide(s) of choice and rhizavidin to the protein(s). The biotin and rhizavidin then bind together through an affinity interaction analogous to Velcro. The construction process is efficient and may significantly reduce the time and cost of vaccine development and production.

Source: Boston Children's Hospital