Evaluation of Chitosan and Its Derivatives in Immunomodulating Blood Sentinel Cells

Opportunistic pathogens can invade and thus cause infections in the body. However, in most instances, the body mounts an immune response to counter the infection. Sentinel cells are the body’s second line of defense, which act against invading microbes. An important part of the innate system, these sentinel cells include macrophages, neutrophils, and dendritic cells. The plethora of pattern recognition receptors helps them to combat the invading pathogen from colonizing the body. They do so by inducing inflammation and oxidative stress or by the adaptive immune cells releasing chemokines. However, a paradigm shift of unrestrained inflammation or oxidative stress can also lead to a hypersensitivity reaction, sepsis, or autoimmune disorder. On the other extreme, an under-responsive sentinel cell might lead to frequent infections. Immunomodulators like chitosan can assist the sentinel cells in the titrated priming of the pathogen, thereby reducing chronic inflammation conditions. Chitosan, the amorphous derivative of chitin is the second largest abundant polymer after cellulose. The physicochemical properties of chitosan and COS depend on molecular weight, degree of polymerization 52(DP), and degree of deacetylation (DD). Thus, the modulation of these properties can impart chitosan and its oligosaccharides (COS) for various biomedical applications. In the present chapter, an overview of the innate responses of the sentinel cells and the synergistic roles played by chitosan and its derivatives to regularize various responses.