Abstract
Glucuronoxylomannan (GXM) is the major capsular polysaccharide of Cryptococcus neoformans. It is essential for fungal virulence and causes a number of deleterious effects to host cells. During the last decades, most of the experimental models designed to study the roles of GXM during cryptococcal infection were based on the stimulation of animal cells. This most commonly involved macrophages or other effector cells, with polysaccharide fractions obtained by precipitation with cationic detergents. More recently, it has been demonstrated that GXM interferes with the physiological state of other target cells, such as the epithelium. In addition, recent studies indicate that the structure of the polysaccharide and, consequently, its functions vary according with the method used for its purification. This raises questions as to what is native GXM and the significance of prior studies. In this paper, we discuss some of the aspects of GXM that are still poorly explored in the current literature, including the relevance of the polysaccharide in the interaction of cryptococci with non-phagocytic cells and the relationship between its structure and biological activity.
Acknowledgements
MLR and LN are supported by grants from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) and Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ, Brazil). AC is supported by NIH grants AI033142, AI033774, AI052733, and HL059842. We are indebted to Dr Rosana Puccia for helpful discussions and Dr Luiz R. Travassos for constant support and mentorship.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.