title: Abrogation of streptococcal pyrogenic exotoxin B-mediated suppression of phagocytosis in U937 cells by Cordyceps sinensis mycelium via production of cytokines.
abstract: Streptococcal pyrogenic exotoxin B (SPE B) is a virulent factor in group A streptococcal infection. We previously showed that SPE B reduced phagocytosis in human monocytic U937 cells. Here we show that the mycelium extract of Cordyceps sinensis (CS), a Chinese immunomodulatory herbal medicine, increased phagocytosis in U937 cells. Neither heat nor trypsin pretreatment prevented CS extract from causing this increase. Further studies indicated that SPE B-mediated suppression of U937 cell phagocytic activity was abrogated by CS extract. Factors in the conditioned medium from CS-extract-treated U937 cells were responsible for blocking the SPE B-mediated suppression of phagocytosis. Heating the conditioned medium eliminated the increase, which suggested that the U937-cell protein products augmented phagocytosis. Analyzing cytokine mRNA expression of U937 cells revealed increases in interferon-gamma (IFN-gamma), interleukin (IL)-12 p35 and p40, and tumor necrosis factor-alpha (TNF-alpha), but not in IL-1beta, IL-6, or IL-8. Treating U937 cells with anti-IFN-gamma, IL-12, and TNF-alpha antibodies also eliminated the conditioned medium-induced increase in phagocytosis. Taken together, SPE B inhibited phagocytosis, but CS mycelium extract abrogated this inhibition by causing cytokine production.
authors.affiliation: Department of Nursing, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Chih-Feng
authors.initials: CF
authors.lastname: Kuo
authors.forename: Cheng-Chih
authors.initials: CC
authors.lastname: Chen
authors.forename: Chiou-Feng
authors.initials: CF
authors.lastname: Lin
authors.forename: Ming-Shiou
authors.initials: MS
authors.lastname: Jan
authors.forename: Robert Y
authors.initials: RY
authors.lastname: Huang
authors.forename: Yueh-Hsia
authors.initials: YH
authors.lastname: Luo
authors.forename: Woei-Jer
authors.initials: WJ
authors.lastname: Chuang
authors.forename: Chia-Chin
authors.initials: CC
authors.lastname: Sheu
authors.forename: Yee-Shin
authors.initials: YS
authors.lastname: Lin
mesh_terms: D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000633:toxicity*; D032661:Cordyceps / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis* / Q000276:immunology / Q000494:pharmacology; D005098:Exotoxins / Q000037:antagonists & inhibitors / Q000633:toxicity*; D005453:Fluorescence; D006358:Hot Temperature; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D025282:Mycelium / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects*; D013297:Streptococcus pyogenes / Q000378:metabolism; D014357:Trypsin / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D005098:Exotoxins; D007166:Immunosuppressive Agents; C027951:erythrogenic toxin; D014357:Trypsin