title: Enhancement of cytotoxicity of NK cells by D-Fraction, a polysaccharide from Grifola frondosa.
abstract: In innate immunity, activated natural killer (NK) cells attack and damage pathogens such as bacteria and virus without restriction by the MHC antigen. NK cells activated by IL-12 have been reported to recognize and kill tumor cells in perforin-mediated apoptosis. We have reported that D-Fraction, a polysaccharide extracted from the maitake mushroom (Grifola frondosa), activates macrophages, dendritic cells, and T cells and inhibits the growth of tumor cells. However, the effects of D-Fraction on NK cell function in the innate immune response are not well known. In the present study, we administered D-Fraction to MM-46 mammary tumor-bearing C3H/HeJ mice intraperitoneally for 3 consecutive days and investigated its effects on the activation and cytotoxicity of NK cells. D-Fraction significantly enhanced the cytotoxicity against NK-sensitive YAC-1 cells and the expression of CD223 on NK cells. D-Fraction also increased the expression of CD86 on macrophages. In addition, the levels of IL-12 in the culture supernatant of whole spleen cells and in serum increased, compared with the control corresponding to an increase in expression of IL-12 receptor betaI on NK cells. These results suggest that D-Fraction enhances the cytotoxicity of NK cells through the production of IL-12 by macrophages activated by D-Fraction.
authors.affiliation: Department of Microbial Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama-kitamachi, Higashinada-ku, Kobe 658-8558, Japan. n-kodama@kobepharma-u.ac.jp
authors.forename: Noriko
authors.initials: N
authors.lastname: Kodama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Asakawa
authors.forename: Akio
authors.initials: A
authors.lastname: Inui
authors.forename: Yuki
authors.initials: Y
authors.lastname: Masuda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nanba
mesh_terms: D000818:Animals; D005260:Female; D048691:Grifola / Q000737:chemistry*; D018664:Interleukin-12 / Q000096:biosynthesis / Q000378:metabolism; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000502:physiology*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D051379:Mice; D008809:Mice, Inbred C3H; D010936:Plant Extracts / Q000494:pharmacology; D011134:Polysaccharides / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D011134:Polysaccharides; D018664:Interleukin-12