Identification of the protein components of protein-bound polysaccharide (PSK) that interact with NKL cells.
We identified the protein components of a protein-bound polysaccharide (PSK) that are responsible for the biological function of this immunomodulator in its interaction with NKL cells, an NK-derived cell line previously known to be activated by this extract, obtained from the basidiomycete Coriolus versiocolor. In addition, we show that PSK protein interacts with NKL cells through a different receptor from that used by IL-2. This was deduced from the different molecular weights of the PSK/NKL and IL-2/NKL receptor complexes. We show that PSK is composed of a highly glycosylated 12-kDa protein. Protein-bound polysaccharide interacts in vitro with an NKL receptor of approximately 48 kDa, whereas IL-2 shows a similar interaction with NKL receptor proteins of approximately 64 and 75 kDa. Our results may explain why PSK and IL-2 use completely different intracellular routes for their biological activities in NKL cells-i.e., regulating different PKC isozymes, mitogen-activated protein kinases, and nuclear transcription factors.
Jiménez
Eva
E
Servicio de Análisis Clínicos e Inmunología, Hospital Universitario Virgen de las Nieves, Avda. de las Fuerzas Armadas 2, 18014 Granada, Spain.
Garcia-Lora
Angel
A
Martinez
Marisol
M
Garrido
Federico
F
D000970:Antineoplastic Agents / Q000494:pharmacology; D006801:Humans; D007155:Immunologic Factors / Q000378:metabolism*; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects*; D011134:Polysaccharides / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism*
D000970:Antineoplastic Agents; D007155:Immunologic Factors; D007376:Interleukin-2; D011134:Polysaccharides; D011509:Proteoglycans; C010770:polysaccharide-K