chTNT-3/hu IL-12 fusion protein for the immunotherapy of experimental solid tumors.
Fusion proteins are emerging as a promising approach for targeting cytokines to the tumor site in order to generate an effective anti-tumor response. In this study, a fusion protein, chTNT-3/huIL-12, consisting of the necrosis targeting antibody, chTNT-3, and human interleukin-12 (IL-12), was constructed and expressed using the glutamine synthetase gene amplification system in NS0 cells. For these studies, IL-12 was chosen since it has been shown to be a powerful anti-tumor cytokine. To generate the fusion protein, an expression vector was prepared by linking the huIL-12 p35 subunit cDNA to the 3' end of the chTNT-3 heavy chain cDNA and the p40 subunit was added to a separate vector. The activity of the expressed chTNT-3/huIL-12 was confirmed by standard IL-12 bioactivity assays which demonstrated that the fusion protein induced similar levels of peripheral blood lymphocyte (PBL) proliferation as free recombinant IL-12. In addition, the lytic activity of the fusion protein was demonstrated in both naive and IL-2-activated lymphocytes using cytotoxicity assays against three human pancreatic and prostatic cancer cell lines (CAPAN, DU145, and PC3-MA). Human PBL incubated with this fusion protein showed an increase in IFN-gamma production which was augmented dramatically by pre-incubation with IL-2. Finally, the immunotherapeutic potential of the fusion protein was demonstrated in the human PBL-SCID mouse model where a 44% reduction in DU145 prostatic tumor growth was obtained compared to control treated mice. These results demonstrate that tumor-targeted human IL-12 may be an effective immunotherapeutic reagent for the treatment of solid tumors in man.
Li
Jiali
J
Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA.
Hu
Peisheng
P
Khawli
Leslie A
LA
Yun
Aoyun
A
Epstein
Alan L
AL
D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D005260:Female; D006801:Humans; D007167:Immunotherapy; D018664:Interleukin-12 / Q000235:genetics / Q000627:therapeutic use*; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000627:therapeutic use*
D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D018664:Interleukin-12