In the preceding chapter (Part 1), the authors described the origin of galectins while focusing on the point that galectins are essentially cytosolic proteins1. In this chapter, one of the authors (J.H.) hypothesizes that the presence of carbohydrates is prerequisite to the generation of lectins that recognize them as counterpart molecules, and that the presence of galactose (the carbohydrate ligand of galectin) is prerequisite to the generation of galectin. Clearly, the question is: what is the origin of galactose? In this chapter and as previously proposed by Hirabayashi (for details, see refs. 1-4), a hypothesis regarding the “late arrival of galactose” and the origin of saccharides is presented. ...and more
The polysaccharide, chitin, is the main component of crab shells, which is an abundant biomass. But it has poor solubility, so it is rarely used. Recently, a mechanical treatment technique for converting chitin into "nano-chitin" has been developed. Nanochitin is a fine fibrous substance with a width of about 10 nm and uniformly dispersible in water, so it is easy to process. Since it is also possible to search for functions, various functions have been clarified. Nanochitin has an effect on the skin, an effect associated with oral administration, and an effect on plants sprayed with it. It is expected that the utilization of the new materials derived from these unused resources will be promoted by clarifying unknown potential functions. ...and more
IgG activates FcγRs and the complement system while intravenous immunoglobulin (IVIG) consisting of plasma IgG exerts anti-inflammatory effects in the treatment of autoimmune diseases. Although IVIG has been used for >40 years as a treatment option for certain autoimmune disorders, its mechanism of action (MOA) remains unsolved. Recently developed chemo-enzymatic glycoengineering approach allows for remodeling of the Fc glycans of polyclonal IgG. We prepared fucosylated or nonfucosylated plasma IgG glycoforms having 2 sialic acids, 2 galactose, or 0 galactose at the nonreducing ends of the Fc glycans to investigate their anti-inflammatory activity. We have demonstrated that the galactosylated, nonfucosylated [(G2)2] glycoform has the highest affinity for FcγRIIIa and potency to inhibit antibody-dependent cellular cytotoxicity (ADCC) activity of immune cells. As the (G2)2 glycoform is a component of IVIG, glycoengineered IVIG consisting of the (G2)2 glycoform alone may be a potential next-generation antibody drug. This review outlines our current understanding of the role of IgG-Fc glycan in MOA of IVIG. ...and more
