title: Advantages of adoptive chemoimmunotherapy with polyethylene glycol-cultured, antigen-activated, tumor-infiltrated spleen cells for the complete eradication of lethal MOPC-315 plasmacytomas.
abstract: The incorporation of polyethylene glycol-6000 (PEG) into the culture media of tumor-infiltrated spleen cells (TISpC) and MOPC-315 stimulator tumor cells at a responder to stimulator cell ratio of 30/1 had been shown to lead to the appearance of CD8+ T-cells that were effective in adoptive chemoimmunotherapy (ACIT) of mice bearing a barely palpable MOPC-315 tumor (J. A. Wise, M. B. Mokyr, and S. Dray, Cancer Res., 49:3613-3619, 1989). Here we show that in the presence of substantially fewer added stimulator tumor cells (responder to stimulator cell ratio, 100/1), the inclusion of PEG in the cultures of TISpC also enhanced the appearance of cells that were highly effective in curing such mice by ACIT. Moreover, these PEG-cultured TISpC were more effective in ACIT than TISpC cultured in the presence of an optimal concentration of recombinant interleukin-2 (60 IU/ml). The potency of the tumor-eradicating activity of the PEG-cultured TISpC in ACIT was further illustrated by their ability to cause the complete regression of a large (20-22 mm) s.c. MOPC-315 tumor in conjunction with a dose of drug that by itself did not cause tumor regression. PEG-cultured TISpC that were effective against MOPC-315 tumor cells in an antigen-specific manner. In fact, PEG-cultured TISpC were more effective than recombinant interleukin-2-cultured TISpC, not only in ACIT, but also in their ability to lyse MOPC-315 tumor cells in vitro. Thus, a direct specific lytic activity against the tumor by cytotoxic T-lymphocytes is the apparent mechanism through which the complete regression of the large tumor burden is brought about by the PEG-cultured TISpC. Finally, we suggest that the incorporation of PEG to render ineffective lymphoid cells effective in ACIT may offer some advantages compared with the incorporation of recombinant interleukin-2 and may be suitable for protocols to generate human cytotoxic cells for cancer therapy when there are relatively low numbers of available tumor cells.
authors.affiliation: Department of Microbiology and Immunology, University of Illinois, Chicago 60680.
authors.forename: M
authors.initials: M
authors.lastname: Laude
authors.forename: K L
authors.initials: KL
authors.lastname: Siessmann
authors.forename: M B
authors.initials: MB
authors.lastname: Mokyr
authors.forename: S
authors.initials: S
authors.lastname: Dray
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005260:Female; D016219:Immunotherapy, Adoptive / Q000379:methods*; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation; D016246:Lymphocytes, Tumor-Infiltrating / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010954:Plasmacytoma / Q000628:therapy*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D012074:Remission Induction; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D007376:Interleukin-2; D011994:Recombinant Proteins; D011092:Polyethylene Glycols