The capsule is the outermost layer of polymeric molecules in many pathogenic bacteria and certain fungi. Virtually all the capsules are made of polysaccharides with extreme diversity in structure among bacteria. Structural diversity is also found among strains of the same bacteria, which is the basis of ...
The capsule is the outermost layer of polymeric molecules in many pathogenic bacteria and certain fungi. Virtually all the capsules are made of polysaccharides with extreme diversity in structure among bacteria. Structural diversity is also found among strains of the same bacteria, which is the basis of serological typing. The capsules enhance bacterial survival in mammalian hosts, which agrees with the findings of many in vitro studies that the capsules diminish the affinity of immune cells and molecules to encapsulated bacteria. The well-known or “old” structure of the capsule –a series of recent studies have reminded us of important knowledge gaps in our understanding of the capsules as virulence factors, vaccine antigens and molecular tools in biotechnological applications. For example, the liver macrophage Kupffer cells have been identified as the major target cell for immune evasion during blood-borne bacterial infections. And capsular polysaccharide-based vaccines enable the liver to capture otherwise “untouchable” encapsulated pathogens while some technical difficulties remain in the production of polysaccharide vaccines. Furthermore, genomic studies have uncovered capsule biosynthesis gene clusters in a large number of bacteria, but the biochemical natures of capsule biosynthesis are only partially characterized in a few species. Along this line, the majority of published bacterial genomes, including those of many commensal bacteria, contain capsule biosynthesis genes, implying that the capsules have additional uncharacterized activities beyond their functions in the immune evasion of pathogens. In addition, the biophysical properties of capsular materials may be also used for drug delivery and other biotechnological applications.
This research topic aims to promote our understanding of broad aspects of capsule biology and application with specific areas as listed below.
• Mechanisms of capsule interactions with host cells and molecules
• Capsule biosynthesis
• Contribution of the capsules to the life of non-pathogenic bacteria
• Regulatory mechanisms of capsule production
• Bio-conjugation of capsular polysaccharides to carriers for vaccine development
• Application of capsules to drug delivery and other needs
Keywords:
bacterium, capsule biology, structural/antigenic diversity, biotechnological application, molecular pathogenesis
Important Note:
All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.