Antitumor effector mechanism at a distant site in the double grafted tumor system of PSK, a protein-bound polysaccharide preparation.
The antitumor effect at a distant site of PSK, a Coriolus preparation, was analyzed with the double grafted tumor system in which BALB/c mice received simultaneous intradermal inoculations of Meth-A tumor in the right (10(6) cells) and left (2 x 10(5) cells) flanks and were then injected with PSK in the right-flank tumor on day 3. PSK inhibited the growth of not only the right but also the left (non-treated) tumor. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of 5 mg of PSK and were injected into the Meth-A tumor on day 3. Adoptive transfer of PSK immunized spleen cells caused the complete regression of Meth-A tumors. The effector cell activity was lost only after treatment with anti-Lyt-1 monoclonal antibody plus complement. Spleen cells and right and left regional lymph node cells prepared from PSK immunized mice were examined for Thy-1, Lyt-1, Lyt-2 and asialo GM1 phenotypes. The number of Lyt-1-positive lymphocytes increased in the right regional lymph nodes after intratumoral administration of PSK. A massive accumulation of macrophages and polymorphonuclear leukocytes was found in the right tumor and an infiltration of macrophages and Lyt-2-positive lymphocytes was found in the left (non-treated) tumor by immunohistochemical analyses. These results suggest that intratumoral administration of PSK induces Lyt-1-positive cells first in regional lymph nodes, then in the spleen, and subsequently induces macrophages and Lyt-2-positive cells in the left (non-treated) tumor, thus bringing about the regression of metastatic tumors.
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D002470:Cell Survival; D003165:Complement System Proteins / Q000502:physiology; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D011509:Proteoglycans / Q000627:therapeutic use*; D013154:Spleen / Q000166:cytology / Q000276:immunology
D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D011509:Proteoglycans; C010770:polysaccharide-K; D003165:Complement System Proteins