The prevention of disease and infection requires immune systems that operate effectively. This is accomplished by the elimination of infections and abnormal cells. Immune or biological therapy treats disease by either stimulating or inhibiting the immune system, dependent upon the circumstances. In plants, animals, and microbes, polysaccharides are abundant biomacromolecules. Due to the intricacy of their structure, polysaccharides may interact with and impact the immune response; hence, they play a crucial role in the treatment of several human illnesses. There is an urgent need for the identification of natural biomolecules that may prevent infection and treat chronic disease. This article addresses some of the naturally occurring polysaccharides of known therapeutic potential that have already been identified. This article also discusses extraction methods and immunological modulatory capabilities.

We report here a successful expression of a single-module GH-7 family cellobiohydrolase Cel7A from a thermophilic fungus Talaromyces emersonii (Te Cel7A) in Saccharomyces cerevisiae. The heterologous expression system allowed structure-guided protein engineering to improve the thermostability and activity of Te Cel7A. Altogether six different mutants aimed at introducing additional disulphide bridges to the catalytic module of Te Cel7A were designed. These included addition of five individual S-S bridges in or between the loops extending from the β-sandwich fold, and located either near the active site tunnel or forming the tunnel in Te Cel7A. A triple mutant containing the three best S-S mutations was also engineered. Three out of five single S-S mutants all had clearly improved thermostability which was also reflected as improved Avicel hydrolysis efficiency at 75°C. The best mutant was the triple mutant whose unfolding temperature was improved by 9°C leading to efficient microcrystalline cellulose hydrolysis at 80°C. All the additional S-S bonds contributed mainly to the thermostability of the Te Cel7A, but one of the mutants (N54C/P191C) also showed, somewhat surprisingly, improved activity even at room temperature.