title: Prophylactic intervention in radiation-leukemia-virus-induced murine lymphoma by the biological response modifier polysaccharide K.
abstract: Polysaccharide K (PSK) is a biological response modifier used for adjuvant immunotherapy of malignant diseases. We studied the potential applicability of PSK for preventing tumor progression using an experimental model of murine lymphoma. Mice inoculated with the radiation leukemia virus (RadLV) develop thymic lymphomas after a latency of 3-6 months. However, 2 weeks after virus inoculation, prelymphoma cells can already be detected in the thymus. We found that PSK treatment induced hyperresponsiveness to concanavalin A and heightened production of interleukin-2 (IL-2) and IL-4 in spleen cells of both control and prelymphoma mice. The response was transient and was accompanied with a dominant usage of T cells expressing V beta 8, but other T cell subsets were also stimulated by PSK. T lymphoma cells expressing V beta 8.2 underwent apoptosis when incubated with PSK. Treatment of RadLV-inoculated mice with PSK delayed the onset of overt lymphoma (and mortality) but could not protect the mice from the disease. Combined treatment with PSK and a RadLV-specific immunotoxin prevented synergistically the progression of the prelymphoma cells to frank lymphoma. The results suggest that PSK contains a superantigen-like component that selectively activates V beta 8+ T cells. Its administration prelymphoma mice interfered with the process of lymphoma progression.
authors.affiliation: Lautenberg Center for General and Tumor Immunology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Yefenof
authors.forename: I
authors.initials: I
authors.lastname: Gafanovitch
authors.forename: E
authors.initials: E
authors.lastname: Oron
authors.forename: M
authors.initials: M
authors.lastname: Bar
authors.forename: E
authors.initials: E
authors.lastname: Klein
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology / Q000627:therapeutic use*; D017668:Age of Onset; D000818:Animals; D017951:Antigen Presentation; D017209:Apoptosis; D005260:Female; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D007167:Immunotherapy; D008213:Lymphocyte Activation / Q000187:drug effects; D008212:Lymphocyte Depletion; D008223:Lymphoma / Q000276:immunology / Q000628:therapy* / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL; D011230:Precancerous Conditions / Q000276:immunology / Q000628:therapy* / Q000821:virology; D011509:Proteoglycans / Q000494:pharmacology / Q000627:therapeutic use*; D016721:Radiation Leukemia Virus; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D012192:Retroviridae Infections / Q000276:immunology / Q000628:therapy*; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D013953:Thymus Neoplasms / Q000276:immunology / Q000628:therapy* / Q000821:virology; D014412:Tumor Virus Infections / Q000276:immunology / Q000628:therapy*
chemical_list: D000276:Adjuvants, Immunologic; D011509:Proteoglycans; D016693:Receptors, Antigen, T-Cell, alpha-beta; C010770:polysaccharide-K