Enhancement of effector cell activities in mice bearing syngeneic plasmacytoma X5563 by a biological response modifier, PSK.
We investigated the effect of PSK, a protein-bound polysaccharide obtained from Coriolus versicolor of basidiomycetes, on antitumor immunity in tumor-bearing mice. PSK prolonged significantly the life span of C3H/He mice bearing syngeneic plasmacytoma X5563 in a schedule- and dose-dependent manner. PSK was most effective when administered at 100 mg/kg every other day ten times starting from the day after tumor inoculation. The administration of PSK enhanced significantly the cytostatic activity of peritoneal exudate plastic-adherent cells and the cytolytic activity of spleen cells after in vitro incubation with mitomycin C-treated tumor cells. In addition, PSK restored the cytokine-producing capacity of spleen cells suppressed in tumor-bearing mice after in vitro incubation with mitogen. Sera from tumor-bearing mice suppressed the activity of such effector cells as well as the interleukin 2-producing capacity of spleen cells, but sera from PSK-treated tumor-bearing mice prevented this suppression. These results suggest that PSK enhances antitumor immunity by reducing immunosuppressive activity of serum from tumor-bearing mice.
Matsunaga
K
K
Biomedical Research Laboratories, Kureha Chemical Industry, Co., Ltd., Tokyo, Japan.
Iijima
H
H
Aota
M
M
Oguchi
Y
Y
Fujii
T
T
Yoshikumi
C
C
Nomoto
K
K
D000276:Adjuvants, Immunologic / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001201:Ascites / Q000473:pathology; D016207:Cytokines / Q000378:metabolism; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D007155:Immunologic Factors / Q000494:pharmacology* / Q000627:therapeutic use; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008809:Mice, Inbred C3H / Q000276:immunology; D009368:Neoplasm Transplantation; D010954:Plasmacytoma / Q000276:immunology* / Q000628:therapy; D011509:Proteoglycans / Q000494:pharmacology* / Q000627:therapeutic use; D013154:Spleen / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000187:drug effects* / Q000378:metabolism
D000276:Adjuvants, Immunologic; D016207:Cytokines; D007155:Immunologic Factors; D011509:Proteoglycans; C010770:polysaccharide-K