Suchergebnisse

Infectious diseases are now emerging or reemerging almost every year. This trend will continue because a number of factors, including the increased global population, aging, travel, urbanization, and climate change, favor the emergence, evolution, and spread of new pathogens. The approach used so far for emerging infectious diseases (EIDs) does not work from the technical point of view, and it is not sustainable. However, the advent of platform technologies offers vaccine manufacturers an opportunity to develop new vaccines faster and to reduce the investment to build manufacturing facilities, in addition to allowing for the possible streamlining of regulatory processes. The new technologies also make possible the rapid development of human monoclonal antibodies that could become a potent immediate response to an emergency. So far, several proposals to approach EIDs have been made independently by scientists, the private sector, national governments, and international organizations such as the World Health Organization (WHO). While each of them has merit, there is a need for a global governance that is capable of taking a strong leadership role and making it attractive to all partners to come to the same table and to coordinate the global approach.

Technological advances, together with a better understanding of the molecular biology of infectious microorganisms, are creating exciting possibilities for a new generation of replicating vaccines. Historically, live vaccines have been either directly derived from a natural source or attenuated by empirical approaches using serial passages and host cell adaptation. Currently, we are witnessing a quantum leap in our technological capabilities to specifically modify the genetic make-up of viruses and bacteria, making it possible to generate improved live vaccines and to develop completely new types of replicating vaccines, such as vectored vaccines, single-round infectious vaccines and replicon vaccines. This book highlights some of the most exciting recent developments towards a new generation of replicating vaccines.

Copyright © 2020 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). ; Meningococcal meningitis remains a substantial cause of mortality and morbidity worldwide. Until recently, countries in the African meningitis belt were susceptible to devastating outbreaks, largely attributed to serogroup A Neisseria meningitidis (MenA). Vaccination with glycoconjugates of MenA capsular polysaccharide led to an almost complete elimination of MenA clinical cases. To understand the molecular basis of vaccine-induced protection, we generated a panel of oligosaccharide fragments of different lengths and tested them with polyclonal and monoclonal antibodies by inhibition enzyme-linked immunosorbent assay, surface plasmon resonance, and competitive human serum bactericidal assay, which is a surrogate for protection. The epitope was shown to optimize between three and six repeating units and to be O-acetylated. The molecular interactions between a protective monoclonal antibody and a MenA capsular polysaccharide fragment were further elucidated at the atomic level by saturation transfer difference NMR spectroscopy and X-ray crystallography. The epitope consists of a trisaccharide anchored to the antibody via the O- and N-acetyl moieties through either H-bonding or CH–π interactions. In silico docking showed that 3-O-acetylation of the upstream residue is essential for antibody binding, while O-acetate could be equally accommodated at three and four positions of the other two residues. These results shed light on the mechanism of action of current MenA vaccines and provide a foundation for the rational design of improved therapies. ; This work was sponsored by GlaxoSmithKline Biologicals and has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement 675671. ; info:eu-repo/semantics/publishedVersion