Journal of immunotherapy with emphasis on tumor immunology : official journal of the Society for Biological Therapy最新文献

Patients with advanced malignancies, participating in our ongoing phase I interleukin-4 (IL-4) gene therapy protocol at the Pittsburgh Cancer Institute, were vaccinated with irradiated autologous tumor cells together with IL-4 gene-transduced irradiated autologous fibroblasts. The level of expression of the IL-4 gene in cultured transduced and selected fibroblasts and in biopsies obtained from vaccination sites was evaluated using quantitative reverse transcription-polymerase chain reaction (RT-PCR). The number of copies of IL-4 mRNA/ng of total cellular RNA was determined in the transduced fibroblasts. Good agreement was observed between IL-4 message expression, as determined by RT-PCR, and IL-4 production, as determined by enzyme-linked immunosorbent assay (ELISA) in the fibroblast supernatants. Tissue biopsies of multiple vaccination sites were obtained from the patients to determine the level of gene expression in situ for IL-4 and Neo-r. The Neo-r gene was used as a marker for transduced fibroblasts. Two weeks after the first vaccination, mRNA for the IL-4 gene was still detectable in all tissue biopsies. The Neo-r gene was also detectable, indicating the presence of transduced fibroblasts in the biopsy. After the second vaccination, expression of the IL-4 and Neo-r genes was generally the highest on day 1 after vaccine administration and was considerably lower but still detectable on day 14 in all biopsies tested. These data indicate that autologous dermal fibroblasts transduced with the IL-4 and Neo-r genes and used as a source of IL-4 in tumor vaccine are able to express the IL-4 gene in vivo.

A recently described tumor-derived glycoprotein, designated 90K, has been shown to have positive effects on the generation of cytotoxic effector cells (NK/LAK) from human PBMC. To determine the mechanism of these effects, we have examined the effects of 90K on cytokine production by human PBMC. A culture of normal PBMC with 90K alone did not result in IL-2 secretion; however, in coculture with suboptimal doses of ConA, 90K increased IL-2 secretion by PBMC. Coculture of PBMC with 90K and ConA also resulted in increased production of the cytokines IL-1, IL-6, GM-CSF, and TNF alpha. T cells depleted of accessory cells failed to respond to ConA alone, 90K alone, or the combination of ConA and 90K, suggesting that this protein does not have a direct effect on T cells. However, 90K alone was sufficient to induce cytokine production by unfractionated PBMC (IL-1, IL-6, GM-CSF, and TNF alpha) or by CD14-enriched PBMC (IL-1 and IL-6). In addition, expression of ICAM-1 was increased on a human monocytic cell line cultured with purified 90K in the absence of any other stimulus. This 90K-induced upregulation of ICAM-1 expression was accompanied by an increased accessory function of the monocytes, demonstrated by their ability to support ConA-induced activation of peripheral blood T cells. Based on the current data, we propose a model in which 90K activates accessory cells, resulting in the secretion of cytokines and the expression of adhesion molecules, which in turn act as costimulatory signals for T-cell activation. Activated T cells then produce cytokines such as IL-2, which lead to a more vigorous cell-mediated immune response to tumor cells and virus-infected cells. Thus, 90K shows promise as an immunotherapeutic reagent for diseases such as cancer and viral infection.

A major limitation of radiolabeled monoclonal antibodies (MAbs) for cancer imaging and therapy is their low accumulation within solid tumors. We, and others, have previously shown that pretreatment of a tumor mass with gamma radiation can increase the level of radiolabeled MAb at the tumor site. Unlike that of conventional radiation, the dose distribution of protons allows for increasing the dose to the cancer volume while reducing the normal tissue dose. The Proton Radiation Therapy Facility at LLUMC treats patients and conducts research. In this study, we sought to determine if preirradiation with proton beam can enhance the localization of radiolabeled MAb within xenotransplanted human colon tumors. T380 colon tumors, implanted s.c. into athymic mice, were subjected to proton irradiation (10 Gy, single dose) when mean tumor volume was 125-135 mm3/group. 111In-ZCE025, a murine MAb directed against carcinoembryonic antigen, was injected i.p. 2 h later, and biodistribution studies were performed 38 h thereafter. Animals irradiated with 60Co and given either 111In-ZCE025 or 111In-MOPC21, an irrelevant MAb, served as controls. The mean percentage of injected radioactivity localized within tumors was highest in the group treated with protons + 111In-ZCE025 when expressed on a per gram basis (%ID/g = 19.3). Somewhat unexpectedly, higher radioactivity was also noted in the normal tissues of these animals compared to other groups. The mean %ID/g tumor values for those given 60Co + 111In-ZCE025 or the antibody alone were 12.5 and 9.0. Our data show that preirradiation of solid tumors increases the localization of tumor-specific radiolabeled MAb at the tumor site.(ABSTRACT TRUNCATED AT 250 WORDS)

We compared the efficacy of gene therapy mediated by interleukin-2 (IL-2) gene-modified tumor cells to gene therapy mediated by IL-2 transduced fibroblasts in the CT-26 model of murine colorectal carcinoma. We transduced CT-26 tumor cells and BALB/c 3T3 fibroblasts with three different retroviral vectors using three different promoters for the human IL-2 gene: DC/TKIL-2 (thymidine kinase promoter), LXSN-iIL2 (long terminal repeat promoter), and LNCX-iIL2 (cytomegalovirus promoter). These transductions resulted in CT-26 and 3T3 subclones that secreted different amounts of IL-2. Immunization of animals with either CT-26/IL-2 cells or with fibroblast/IL-2 cells mixed with CT-26 induced similar levels of immunity that protected 62-82% of animals against a subsequent tumor challenge with parental CT-26. However, mice developed tumors at the site of inoculation in 46% of the animals immunized with CT-26/IL-2 cells. In a separate experiment, CT-26/IL-2 cells were exposed to 6,000 cGy of gamma irradiation to prevent tumor growth at the site of inoculation. Although the CT-26/IL-2 cells continued to secrete IL-2 after irradiation, they were no longer effective at inducing antitumor immunity. In contrast, both irradiated and nonirradiated fibroblast/IL-2 cells, mixed with irradiated CT-26, were equally effective at inducing antitumor immunity. These data suggest that in the CT-26 model, fibroblast-mediated IL-2 gene therapy has advantages for the induction of antitumor immunity and abrogation of tumorigenic potential at the site of inoculation compared with tumor cell-mediated IL-2 gene therapy.

We studied major histocompatibility complex (MHC) class I expression in 12 tumor cell culture lines established from patients with metastatic renal cell carcinoma (RCC). In one of these cell culture lines, UOK 123, we found no surface expression of beta 2-microglobulin (beta 2m) and MHC class I by flow cytometry. Immunofluorescence staining using three different monoclonal antibodies to beta 2m revealed no detectable beta 2m in the endoplasmic reticulum (ER), Golgi apparatus, cytoplasm, or on the cell surface. There was no evidence of folded class I molecules inside or on the surface of the cells; however, the ER stained intensively for unfolded class I molecules. Transient expression of beta 2m by UOK 123 after infection with a recombinant vaccinia virus containing the gene for beta 2m resulted in normal expression of both beta 2m and class I (HLA-A, B, C) determinants assessed by flow cytometry analysis. No expression of class I or beta 2m was seen with the recombinant vaccinia vector carrying a control gene. The inability of class I molecules to reach the cell surface is due to the requirement of beta 2m for proper folding and presentation of the class I MHC complex. The failure to assemble and express MHC class I complex on the cell surface renders these cells incapable of antigen presentation to cytotoxic T cells and provides a mechanism for escape from immune recognition by the tumor.

The aim of this study was to ascertain whether any cytokines that function in earlier stages of hematopoiesis also fluctuate in conjunction with granulocyte colony-stimulating factor (G-CSF) in chemotherapy-induced myelosuppression. A total of seven patients were studied. All patients received 3 days of intravenous injection of combination chemotherapy. Patients' absolute neutrophil count (ANC), platelet count, serum G-CSF, interleukin-6 (IL-6), IL-3, and IL-1 alpha were monitored before chemotherapy, and then daily or every other day thereafter during the entire treatment course until the ANC returned to normal. The results showed very obvious elevation of serum IL-6 level before or concurrent with the elevation of serum G-CSF levels at the neutrophil nadir in all seven patients. The rise of IL-6 also correlated with nadir platelet levels in six of seven patients. The finding of serum IL-6 elevation was statistically significant both in neutropenic and thrombocytopenic stages. Serum IL-3 level was below minimum detectable concentrations in all seven patients. Serum IL-1 alpha was below minimum detectable concentration in six patients and demonstrated no obvious fluctuation in the remaining patient. Therefore, the present study demonstrated the chronological time sequence of cytokine fluctuation, IL-6 peak before G-CSF, in chemotherapy-induced myelosuppression. According to this finding, when cytokines are used for prevention of myelosuppression or for acceleration of its recovery, it may be logical to use a combination of cytokines in sequence, such as IL-6 initially followed by G-CSF.