Antitumor response to recombinant murine interferon gamma correlates with enhanced immune function of organ-associated, but not recirculating cytolytic T lymphocytes and macrophages

Anti-tumor mechanism of Z-100, an immunomodulatory Arabinomannan extracted from Mycobacterium tuberculosis strain Aoyama B, on pulmonary metastases of B16F10 melanoma: restoration of helper T cell responses via suppression of glucocorticoid-genesis

In the present study, the anti-tumor mechanism of Z-100 was investigated with the use of pulmonary metastasis of B16F10 melanoma. In B16F10 mice, Th1 cytokine production (IL-2, IFN-gamma) was suppressed in comparison with normal mice. On the other hand, Th2 cytokine production (IL-4, IL-10) was increased in the B16F10 mice. The administration of Z-100 to B16F10 mice restored the balance of Th1/Th2 cell responses from the Th2 dominant state to the normal state. Z-100 significantly suppressed the pulmonary metastasis of B16F10 melanoma in a dose-dependent manner. These results suggest that Z-100 restored the breakdown of Th1 cell responses, resulting in the suppression of pulmonary metastasis of B16F10 melanoma. Moreover, Z-100 decreased the corticosterone levels, which is known to suppress the Th1 cell responses, in both serum specimens and splenic tissue, and the steroidogenic CYP11A1 mRNA expression in CD4+ T cells. These results suggest that a suppression of pulmonary metastasis and restoration of Thl/Th2 cell responses by Z-100 may be due to the decrease in the corticosterone levels and the steroidogenic CYP11A1 mRNA expression of CD4+ T cells in B16F10 mice. Further, the role of Th1 cytokine, IFN-gamma, on these activities of Z-100 was examined. The suppressive effects of Z-100 on pulmonary metastasis and restoration of Th1/Th2 cell responses were eliminated by the administration of anti-IFN-gamma mAb. Moreover, the suppressive effects of Z-100 on glucocorticoid-genesis were eliminated by the administration of anti-IFN-gamma-mAb. These results suggest that Z-100 restores the balance of Th1/Th2 cell responses via the suppression of glucocorticoid-genesis by Z-100-induced IFN-gamma. IFN-gamma acts as a key cytokine in anti-tumor activities of Z-100.

Significant antitumor effects obtained by autologous tumor cell vaccine engineered to secrete interleukin (IL)-12 and IL-18 by means of the EBV/lipoplex

The EBV/lipoplex is a nonviral gene delivery system composed of a cationic lipid and Epstein-Barr virus (EBV)-based plasmid vector that carries the EBV oriP and EBV nuclear antigen 1 (EBNA1) gene. Because the EBNA1 supports retention, nuclear localization, and transcriptional upregulation of the oriP-bearing plasmid, cells transfected with the EBV/lipoplex express the transgene at a very high level. We hypothesized that tumor cells genetically manipulated with the EBV/lipoplex may be used as a tumor vaccine without drug selection, strongly contributing to immunotherapy of patients with malignancies. The cytokines interleukin (IL)-12 and IL-18 exert a variety of immune-regulatory functions including interferon (IFN)-gamma production and cytotoxic T lymphocyte (CTL) and natural killer (NK) activation. Here, we investigated the possible therapeutic effects of an autologous tumor cell vaccine in the B16 melanoma model. The vaccine was engineered to secrete IL-12 and IL-18 by means of the EBV/lipoplex. B16 cells were subcutaneously implanted into syngenic mice followed by repetitive immunization with irradiated B16 cells that had been transfected 3 days earlier by TFL2-3, a novel cationic lipid, with EBV-plasmid vectors encoding IL-12 and/or IL-18 genes (B16/mIL-12, B16/mIL-18, and B16/mIL-12+mIL-18). The mice vaccinated with B16/mIL-12 underwent strong tumor suppression accompanied by a high IFN-gamma production. Both CTL and NK activities were significantly elevated in these mice. When the tumor cell vaccine was prepared by means of conventional (non-EBV) plasmid vectors combined with the same cationic lipid, the therapeutic outcome was not as good, suggesting the superiority of the EBV-based plasmid in engineering these types of tumor vaccines. Vaccination with B16/mIL-18 was not effective in suppressing tumors, whereas B16/mIL-12+mIL-18 showed comparable antitumor therapeutic validity as B16/mIL-12 did. When IFN-gamma mutant (IFN-gamma(-/-) mice were treated, B16/mIL-12 vaccine did not show any therapeutic activity, suggesting the necessity of IFN-gamma in the anti-melanoma immune responses. In contrast, the antitumor effect was not affected by NK depletion in mice that received repetitive injections with anti-asialo GM1 antibody. Furthermore, vaccination with B16/mIL-12 significantly suppressed pulmonary metastases in mice that had been intravenously injected with parental B16. Our results suggest that the EBV/lipoplex is quite useful in generating an autologous tumor cell vaccine and that IL-12 is an important component of the vaccine.

Effectiveness of IFN-gamma for liver abscesses in chronic granulomatous disease

In chronic granulomatous disease, interferon-gamma (IFN-gamma) significantly reduces the incidence and severity of recurrent infections, but its effectiveness administered ex novo during acute infection has been reported in only one case. In this report, we describe two adult brothers with chronic granulomatous disease treated successfully with IFN-gamma for acute liver abscesses. Two brothers with severe recurrent infections of unknown origin were hospitalized for septic fever, malnutrition, and ultrasonographic evidence of liver abscess. Autosomal recessive chronic granulomatous disease was diagnosed based on lack of superoxide anion production by phagocytes and absence of p47-phox protein. An antibiotic regimen specifically directed against Staphylococcus aureus was ineffective, whereas treatment with 50 microg/m2 IFN-gamma s.c. thrice weekly induced complete healing with scarring within 3 months. No septic recurrence was observed during a 4-year follow-up period. In chronic granulomatous disease, IFN-gamma is effective not only in preventing but also in healing life-threatening acute infections.

Pharmacodynamic aspects of peptide administration biological response modifiers

Cytokines, growth factors and other recombinant proteins have been one of the most rapidly growing areas of pharmaceuticals. Further, the development of these bio-engineered drugs is occurring at an astonishing pace with rapid preclinical and clinical development and licensing by regulatory agencies. In addition, the availability of the gene sequences and rational drug design technologies have resulted in a rapid development of engineered genes, proteins and peptidomimetics. In contrast to traditional pharmacophores, which are developed based on the identification of the maximum tolerated dose (MTD), most recombinant proteins have abnormal biodistributions, and pharmacodynamic and pharmacokinetic attributes. Within this chapter, representative cytokines including interferon-alpha (IFN-alpha), IFN-gamma and interleukin-2 are used to discuss the pharmacodynamic aspects of protein/peptide administration that are important in the development of these drugs. This includes the conceptual need for chronic immunoaugmentation for optimal therapeutic activity; the need to consider the pharmacokinetics of administration to optimize drug delivery and the nonlinear dose response relationship, which can result in a bell shaped dose response. Furthermore, these therapeutics have maximal potential in an adjuvant protocol and their development in combination with high-dose chemotherapy and stem cell rescue is discussed. The strategies for combination chemotherapy and immunotherapy, while holding great promise, require close attention to the pharmacodynamics of protein administration in order to impact on failure free and overall survival.

Prevention of hepatic tumor metastases in rats with herpes viral vaccines and gamma-interferon

Previous studies showed that gammaIFN decreases metastatic hepatic tumor growth by stimulating Kupffer cells (KC). The present studies examine whether lymphocyte stimulation via cells engineered to secrete GM-CSF or IL-2 decreases hepatic tumor growth, and whether stimulation of both macrophages and lymphocytes is more effective than either individually. Rats were immunized with irradiated hepatoma cells transduced by herpes viral amplicon vectors containing the genes for GM-CSF, IL-2 or LacZ. On day 18, half of each group was treated with 5 x 10(4) U gammaIFN, or saline intraperitoneally for 3 d. On day 21, all rats received 5 x 10(5) hepatoma cells intrasplenically. On day 41, rats were killed and tumor nodules were counted. Separate rats underwent splenocyte and KC harvest for assessment of lymphocyte- and macrophage-mediated tumor cell kill in vitro. GM-CSF or IL-2 vaccines or gammaIFN decreased tumor nodules significantly (GM-CSF 13+/-4, IL-2 14+/-6 vs. control 75+/-24, P < 0.001). Combination therapy was more effective, and completely eliminated tumor in 4 of 12 IFN-GM-CSF and 8 of 11 IFN-IL-2 animals. Additional rats underwent partial hepatectomy, an immunosuppressive procedure known to accelerate the growth of hepatic tumor, following tumor challenge. Therapy was equally effective in this immunosuppressive setting. Vaccination is associated with enhancement of splenocyte-mediated tumoricidal activity, whereas the effect of gammaIFN is mediated by KC. GM-CSF and IL-2 vaccine therapy and pretreatment with gammaIFN represent effective strategies in reducing hepatic tumor. Combination therapy targets both lymphocytes and macrophages, and is more effective in reducing tumor than either therapy alone.