RT Journal Article SR Electronic(1) A1 Ren, Yuhao A1 Strobel, Gary A. A1 Graff, Jill C. A1 Jutila, Mark A1 Park, Sung Gyoo A1 Gosh, Sankar A1 Teplow, David A1 Condron, Margaret A1 Pang, Eric A1 Hess, Wilford M. A1 Moore, EmilyYR 2008 T1 Colutellin A, an immunosuppressive peptide from Colletotrichum dematium JF Microbiology, VO 154 IS 7 SP 1973 OP 1979 DO https://doi.org/10.1099/mic.0.2008/017954-0 PB Microbiology Society, SN 1465-2080, AB Colletotrichum dematium is an endophytic fungus recovered from a Pteromischum sp. growing in a tropical forest in Costa Rica. This fungus makes a novel peptide antimycotic, colutellin A, with a MIC of 3.6 μg ml−1 (48 h) against Botrytis cinerea and Sclerotinia sclerotiorum. Collutellin A has a mass of 1127.7 Da and contains residues of Ile, Val, Ser, N-methyl-Val and β-aminoisobutryic acid in nominal molar ratios of 3 : 2 : 1 : 1 : 1, respectively. Independent lines of evidence suggest that the peptide is cyclic and sequences of Val-Ile-Ser-Ile and Ile-Pro-Val have been deduced by MS/MS as well as Edman degradation methods. Colutellin A inhibited CD4+ T-cell activation of interleukin 2 (IL-2) production with an IC50 of 167.3±0.38 nM, whereas cyclosporin A in the same test yielded a value of 61.8 nM. Inhibition of IL-2 production by collutellin A at such a low concentration indicates the potential immunosuppressive activity of this compound. In repeated experiments, cyclosporin A at or above 8 μg ml−1 exhibited high levels of cytotoxicity on human peripheral blood mononuclear cells, whereas collutellin A or DMSO (carrier) alone, after 24 and 48 h of culture, exhibited no toxicity. Because of these properties collutellin A has potential as a novel immunosuppressive drug., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2008/017954-0