Anti-prion activity of protein-bound polysaccharide K in prion-infected cells and animals.

Taichi Hamanaka, Yuji Sakasegawa, Akihiro Ohmoto, Tomohiro Kimura, Takao Ando, Katsumi Doh-ura

Department of Neurochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.

Biochemical and biophysical research communications 2011 Feb 11

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Protein-bound polysaccharide K (PSK) is a clinical immunotherapeutic agent that exhibits various biological activities, including anti-tumor and anti-microbial effects. In the present study, we report on the anti-prion activity of PSK. It inhibited the formation of protease-resistant abnormal prion protein in prion-infected cells without any apparent alterations in either the normal prion protein turnover or the autophagic function in the cells. Its anti-prion activity was predominantly composed of the high molecular weight component(s) of the protein portion of PSK. A single subcutaneous dose of PSK slightly but significantly prolonged the survival time of peritoneally prion-infected mice, but PSK-treated mice produced neutralizing antibodies against the anti-prion activity of PSK. These findings suggest that PSK is a new anti-prion substance that may be useful in elucidating the mechanism of prion replication, although the structure of the anti-prion component(s) of PSK requires further evaluation. Copyright © 2011 Elsevier Inc. All rights reserved.

Citation

Taichi Hamanaka, Yuji Sakasegawa, Akihiro Ohmoto, Tomohiro Kimura, Takao Ando, Katsumi Doh-ura. Anti-prion activity of protein-bound polysaccharide K in prion-infected cells and animals. Biochemical and biophysical research communications. 2011 Feb 11;405(2):285-90