title: IL-2 gene-modified tumour vaccines: monitoring of IL-2 levels in serum and peritoneal cavity of vaccinated mice.
abstract: IL-2 kinetics was assessed in mice vaccinated with irradiated syngeneic tumour vaccines carrying an inserted IL-2 gene and producing constitutively IL-2. For comparison, the kinetics of i.v. administered recombinant IL-2 was also examined. During regular time intervals after the vaccination or administration of recombinant IL-2, samples of serum and peritoneal fluid were collected and examined, using CTLL bioassay or its MTT modification. After i.p. administration of irradiated IL-2-producing plasmacytoma (X63-m-IL-2) vaccine, the levels of IL-2 were substantially higher in the peritoneal fluid than in the serum. Both in the peritoneal fluid and in the serum, the IL-2 level was increasing up to 60 min after administration and then it gradually decreased. The last time point when IL-2 was still detectable both in the peritoneal fluid and in the serum was 30 h. Almost identical results were obtained when the IL-2 levels were detected by the conventional CTLL assay, in which DNA synthesis was monitored by 3H-thymidine labeling, and by the isotope-free MTT modification of the CTLL assay, in which the DNA synthesis was monitored by staining. The MTT modification has the advantage of an isotope-free method. Comparison of two different IL-2-producing vaccines, a murine plasmacytoma X63-m-IL-2, with high IL-2 production, and murine sarcoma MC12-IL-2, with low IL-2 production, revealed that whereas after i.p. administration of the high producers, the peak of IL-2 was reached both in the peritoneal fluid and in the serum after 1 h, the administration of low producers gave the peak level of IL-2 later, 5 h after i.p. administration. Comparison of IL-2 levels obtained after i.p. administration of live and irradiated X63-m-IL-2 vaccine revealed that the irradiated vaccine produced both in vitro and in vivo higher amounts of IL-2. As compared to i.p. administration, the kinetics after i.v. administration of the X63-m-IL-2 vaccine was different. The maximum level of recombinant IL-2 was reached 10 min after administration and IL-2 was undetectable after 5 h. When the injections of recombinant IL-2 were repeated, the elimination of IL-2 from the circulation was substantially faster.
authors.affiliation: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague.
authors.forename: M
authors.initials: M
authors.lastname: Indrová
authors.forename: E
authors.initials: E
authors.lastname: Pajtasz-Piasecka
authors.forename: T
authors.initials: T
authors.lastname: Jandlová
authors.forename: J
authors.initials: J
authors.lastname: Símová
authors.forename: J
authors.initials: J
authors.lastname: Bubeník
authors.forename: C
authors.initials: C
authors.lastname: Radzikowski
mesh_terms: D000818:Animals; D019496:Cancer Vaccines / Q000528:radiation effects; D005354:Fibrosarcoma / Q000473:pathology; D007376:Interleukin-2 / Q000032:analysis / Q000235:genetics* / Q000493:pharmacokinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D010529:Peritoneal Cavity; D010954:Plasmacytoma / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured / Q000528:radiation effects; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000528:radiation effects
chemical_list: D019496:Cancer Vaccines; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic