Immunobiology of Carbohydrates: Implications for Novel Vaccine and Adjuvant Design Against Infectious Diseases.

Giuseppe Stefanetti,Francesco Borriello,Luigi Lay,Ivan Zanoni,Barbara Richichi

doi:10.3389/fcimb.2021.808005

Abstract

Carbohydrates are ubiquitous molecules expressed on the surface of nearly all living cells, and their interaction with carbohydrate-binding proteins is critical to many immunobiological processes. Carbohydrates are utilized as antigens in many licensed vaccines against bacterial pathogens. More recently, they have also been considered as adjuvants. Interestingly, unlike other types of vaccines, adjuvants have improved immune response to carbohydrate-based vaccine in humans only in a few cases. Furthermore, despite the discovery of many new adjuvants in the last years, aluminum salts, when needed, remain the only authorized adjuvant for carbohydrate-based vaccines. In this review, we highlight historical and recent advances on the use of glycans either as vaccine antigens or adjuvants, and we review the use of currently available adjuvants to improve the efficacy of carbohydrate-based vaccines. A better understanding of the mechanism of carbohydrate interaction with innate and adaptive immune cells will benefit the design of a new generation of glycan-based vaccines and of immunomodulators to fight both longstanding and emerging diseases.

Highlights

The Glycocalyx and the Immunomodulatory Role of CarbohydratesCarbohydrates are the most abundant biomolecules on earth and are an essential part of all living organisms (Seeberger and Rademacher, 2014)
Surface polysaccharides are critical for many purposes: they can trigger bacterial adhesion and host cells infection; they exert a protective function against the host’s immune defense, for example interfering with innate immunity by preventing the activation of the alternative complement pathway or by mimicking the host self-antigens; they provide a hydrophilic character to microorganisms that protect them from drying out (Taylor and Roberts, 2005)
This study showed that different mechanisms of presentation, based on the structure of the carbohydrate, are operative in response to different glycoconjugate vaccines (Sun et al, 2019)

Summary

Introduction

The Glycocalyx and the Immunomodulatory Role of CarbohydratesCarbohydrates are the most abundant biomolecules on earth and are an essential part of all living organisms (Seeberger and Rademacher, 2014). The set of cell surface glycoforms constitutes the glycocalyx, a key player in the biology of both eukaryotic and prokaryotic cells, involved in multiple vital cellular processes. The glycocalyx protects the cell from ionic and Immunobiology of Carbohydrates for Vaccines and Adjuvants mechanical stress, preserving the integrity of the membrane and acting as a barrier from invading microorganisms. The glycocalyx plays an essential role in every cellular communication and recognition event and it is critical in determining innate and adaptive immune responses to pathogens and in controlling the growth and spread of cancer (Rabinovich et al, 2012; Mahla et al, 2013; Varki, 2017). Surface polysaccharides are critical for many purposes: they can trigger bacterial adhesion and host cells infection; they exert a protective function against the host’s immune defense, for example interfering with innate immunity by preventing the activation of the alternative complement pathway or by mimicking the host self-antigens; they provide a hydrophilic character to microorganisms that protect them from drying out (Taylor and Roberts, 2005)

Objectives

Conclusion