# Chemical and biological characterization of vaccine adjuvant QS-21 produced via plant cell culture

## TL;DR

Scientists developed a new way to produce a vaccine ingredient called QS-21 using plant cells instead of tree bark, making it more sustainable and accessible.

## Contribution

First-time successful plant cell culture production of QS-21 with properties matching the natural source.

## Key findings

- QS-21 produced via plant cell culture has structural and chemical properties similar to bark-extracted QS-21.
- The new method ensures broader availability and accessibility of QS-21 for vaccine development.
- A sustainable and scalable in vitro platform for producing plant saponin-derived vaccine adjuvants was established.

## Abstract

Many vaccines, including those using recombinant antigen subunits, rely on adjuvant(s) to enhance the efficacy of the host immune responses. Among the few adjuvants clinically approved, QS-21, a saponin-based immunomodulatory molecule isolated from the tree bark of Quillaja saponaria (QS) is used in complex formulations in approved effective vaccines. High demand of the QS raw material as well as manufacturing scalability limitation has been barriers here. We report for the first-time successful plant cell culture production of QS-21 having structural, chemical, and biologic, properties similar to the bark extracted product. These data ensure QS-21 and related saponins are broadly available and accessible to drug developers.

•Transformative method for manufacturing QS-21 vaccine adjuvant•Enhancing the sustainability of QS-21 vaccine adjuvant production•Bioequivalence of plant cell culture and conventional bark extract QS-21 vaccine adjuvants•Revolutionary in vitro platform to develop plant saponin-derived vaccine adjuvants

Transformative method for manufacturing QS-21 vaccine adjuvant

Enhancing the sustainability of QS-21 vaccine adjuvant production

Bioequivalence of plant cell culture and conventional bark extract QS-21 vaccine adjuvants

Revolutionary in vitro platform to develop plant saponin-derived vaccine adjuvants

Natural product synthesis; Medical biochemistry; Cell; Phytochemistry; Bioactive plant product