Effects of satratoxins and other macrocyclic trichothecenes on IL-2 production and viability of EL-4 thymoma cells.
The macrocyclic trichothecenes are a group of potent protein synthesis inhibitors that have been encountered in indoor air and food as a result of infestation by the fungus Stachybotrys. To evaluate the capacity of these mycotoxins to alter immune functions, the effects of satratoxin G, H, F, roridin A, and verrucarin A on interleukin 2 (IL-2) production and viability were evaluated in a murine T-cell model. EL-4 thymoma cells were stimulated with phorbol 12-myristate 13-acetate and ionomycin and concurrently exposed to various concentrations of the trichothecenes. Enzyme-linked immunosorbent assay (ELISA) of supernatants revealed that IL-2 concentrations at 24 and 72 h were significantly increased in cultures that were incubated in the presence of 0.5 to 1 ng/ml of satratoxin H, 1 to 5 ng/ml of isosatratoxin F, 0.1 to 0.5 ng/ml of roridin A, and 0.25 to 0.5 ng/ml of verrucarin A. However, IL-2 levels at these time points were significantly depressed when incubated in the presence of higher concentrations of satratoxin G (> or =2.5 ng/ml), satratoxin H and isosatratoxin F (> or =5 ng/ml), and roridin A and verrucarin A (> or =1 ng/ml). Cell viability, as measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, was depressed by each of the trichothecenes in a concentration-dependent manner. MTT responses were significantly decreased by as little as 0.5 ng/ml satratoxin G, roridin A, and verrucarin A and by 2.5 ng/ml of isosatratoxin F and satratoxin H. When these data were compared to those found in EL-4 cells for the 8-ketotrichothecene vomitoxin (deoxynivalenol), a common food contaminant, the macrocyclic trichothecenes were at least 100 times more potent. The results indicate that, at low concentrations, macrocyclic trichothecenes as a group could superinduce IL-2 production even while partially decreasing cell viability, whereas higher concentrations suppressed cytokine production and were markedly cytotoxic. The capacity of these compounds to dysregulate cytokine production in a biphasic fashion may play an etiologic role in outbreaks of human illnesses associated with indoor Stachybotrys contamination.
Lee
M G
MG
Department of Food Science and Human Nutrition, National Food Safety and Toxicology Center, Michigan State University, East Lansing 48824-1224, USA.
Li
S
S
Jarvis
B B
BB
Pestka
J J
JJ
D000391:Air Microbiology; D016902:Air Pollution, Indoor; D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005516:Food Microbiology; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D013191:Stachybotrys / Q000254:growth & development / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects* / Q000276:immunology; D014255:Trichothecenes / Q000494:pharmacology*
D007166:Immunosuppressive Agents; D007376:Interleukin-2; D011500:Protein Synthesis Inhibitors; D014255:Trichothecenes; C028268:satratoxin G; C014184:satratoxin H; C007262:deoxynivalenol; C005348:muconomycin A; C038849:roridin A