Biomedical subjects
Publications and source records attributed to C L Hyatt.
Studies of recombinant interleukin-2 (RIL-2) administered by continuous intravenous infusion revealed hepatocellular toxicity and redistribution of lymphoid cells. This finding was different from the normal findings seen in rats receiving comparable infusions of the vehicle.
Immunotherapy utilizing the adoptive transfer of lymphokine activated killer (LAK) cells in conjunction with recombinant interleukin 2 (RIL-2) is capable of reducing established metastatic cancer in a variety of animal tumor models. A major difficulty in the application of these efforts to the treatment of human cancer has been the activation in vitro of up to 2 X 10(11) human peripheral blood lymphocytes obtained by repeated leukaphereses. We have thus developed optimal and simplified techniques for the generation of human LAK cells for use in clinical trials. We have found that 1.5 X 10(9) lymphocytes separated on Ficoll-Hypaque gradients and incubated in 1000 ml of culture medium in a 2.3 liter roller bottle with 1000-1500 U of RIL-2 per ml, generated LAK cells capable of killing fresh human tumor cells in a 4 h chromium release assay. The culture medium used was RPMI 1640 with 2 mM glutamine, 2% heat-inactivated human AB serum, 50 micrograms/ml streptomycin and gentamicin and 50 U/ml penicillin. This technique allows activation of sufficient numbers of cells in a research laboratory setting to conduct human clinical trials. The administration of LAK cells generated in this fashion can mediate the regression of human tumors when administered in conjunction with IL-2.
The recent availability of recombinant human interleukin-2 (RIL-2) has increased interest in the potential clinical use of this lymphokine. We have examined the biologic effects of intermittent bolus and continuous intravenous administration of RIL-2 in rats. The mean (+/- SEM) half-life after an intravenous bolus injection of RIL-2 was determined to be 2.9 +/- 0.5 min (n = 4). The administration of intermittent intravenous bolus injections of RIL-2 of doses up to 10(6) units/kg every other day for 2 weeks was well tolerated without toxicity as determined by organ histology and serum chemistries. The continuous intravenous infusion of RIL-2 through an indwelling external jugular vein catheter was tolerated for 2 weeks at doses less than or equal to 3,000 U/kg/h and was associated with no abnormal serum chemistries or organ pathology. By contrast, animals that received less than 10,000 U/kg/h demonstrated RIL-2 toxicity leading to death of treated rats. Serum chemistries revealed a fourfold increase in serum glutamate oxaloacetic transaminase and serum glutamate pyruvic transaminase. Liver histology revealed hepatocellular necrosis with mononuclear cell infiltration. The thymus was depleted of lymphocytes and lymphoid infiltrates were present in liver, spleen, and lung. This is the first documentation of toxicity secondary to RIL-2 administration and suggests that hepatopathy may be the dose-limiting toxicity accompanying the administration of RIL-2.
Certain in vivo and in vitro immunologic features of carcinogen-induced murine bladder cancer have been studied. The consistency of tumor induction, its natural history, and immunogenicity both in vivo and in vitro render this syngeneic murine bladder tumor a suitable model for immunologic studies. Pre-immunization of strain C3H/Hen mice with mid-gestational fetal cells did not protect the animals from tumor challenge. Sera of mice immunized with mid-gestational fetal cells were not cytotoxic to cultured tumor cells in a microcytotoxicity assay indicative of dissimilarity between the tumor associated antigen and the syngeneic mid-gestational fetal antigen.
In vivo and in vitro immunologic cross reactivity between SV40 virus transformed prostatic tissue and fetal antigens of LVG/LAK strain hamsters has been studied. The hamsters immunized with fetal antigens demonstrated significant resistance to tumor growth. Complement-dependent humoral cytotoxicity of target SV40 tumor cells in microtest plates was used to demonstrate the presence of significant antibody titer in fetal-immunized hamsters. When the immune sera were absorbed with SV40 transformed prostatic tissue, cytotoxicity indices were markedly lower than with the unabsorbed immune sera. The transformed prostatic tissue was found to have an elevated tartrate inhibited acid phosphatase indicative of the presence of epithelial components in the transformed tissue. These experiments demonstrate in vivo and in vitro cross reactviity between fetal antigens and tumor associated antigens of transformed prostatic tissue. This study suggests a similarity between fetal antigens and antigens of a specific organ tissue (prostate) transformed by a DNA oncogenic virus.