摘要:

Tumor-infiltrating lymphocytes (TIL) have been successfully used for the treatment of metastatic malignancies in clinical trials and in experimental animal models. Tumor-specific reactivity by TIL is mediated via receptors expressed on the surface of T cells (TcRs), which recognize tumor-associated antigens (TAA) presented in the context of MHC molecules on the surface of tumor cells. The current study was performed to identify the TcR a and P chains from a tumor-specific therapeutic TIL clone that can be used to develop a preclinical animal model for genetically modifying lymphocytes and hematopoietic progenitors with TcR genes. TIL 205 was generated from a subcutaneous implant of MCA-205 fibrosarcoma and at 21 days was cloned by limiting dilution. TIL clone 8, obtained from a culture seeded at one cell/well, mediated specific lysis and specific secretion of 7-interferon to MCA-205 and WP6, a subclone of MCA 205. No reactivity was observed against other syngeneic sarcoma lines. Anchor polymerase chain reaction analysis determined that antigen recognition by clone 8 was mediated by a TcR consisting of Va3/Ja27 and Vp8.2/Dp2.1/Dp2.4. Immunofluorescent staining with Vp subfamily specific monoclonal antibodies revealed that >95% of the T cells in TIL clone 8 expressed VP8.2, confirming that TIL clone 8 was indeed a clone. In contrast, -30% of the T cells in the parental TIL 205 expressed Vp8.2. The transfer of as few as 500,000 TIL clone 8 cells in conjunction with the systemic administration of recombinant human interleukin-2 mediated regression of established 3-day WP6 lung metastases. Thus, clone 8 recognizes a biologically relevant tumor rejection antigen, making the Va3/Ja27-Vp8.2/Dp2.1/jp2.4 TcR isolated from this clone useful as a probe for cloning the tumor-rejection antigen in the WP6 tumor as well as modeling, in mice, the TcR-based gene therapies being developed for humans

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

To obtain more effective cytotoxic T lymphocytes (CTLs), we examined the effect of B7 costimulation and interleukin-12 (IL-12) on the induction of allogeneic CTLs. Peripheral blood lymphocytes (PBLs) or positively selected human CD8+ T cells (purity >99%) from healthy donors were used as effector cells, and B7-1- transfected or nontransfected U251 human glioma cells (U251-B7 or U251-Vec.) were used as stimulator cells. In mixed lymphocyte culture (MLC) with PBLs and U251 cells, nonspecific natural killer (NK) activity was raised by addition of IL-12, and the effect of B7 costimulation was not observed. However, in MLC with CD8+T cells, efficient proliferation, generation of CTLs, and cytokine production were induced by MLC with U251-B7 in the presence of IL-12. Efficient generation of CTLs was not induced by either MLC with U251-B7 alone or the addition of IL-12 alone. Our results indicate that a combination of B7-1 costimulation and IL-12 is effective for inducing generation of CTLs, and that the CD8+T cells can be differentiated into CTLs without the help of CD4+T cells or antigen-presenting cells or both

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The pathobiology of melanomas that develop within the eye is distinct from melanomas that develop within the subcutaneous tissues of the skin. This may be related to the unique structural and functional differences between normal melanocytes present within the uveal tract of the eye and the epidermal layers of the skin. The purpose of the present study was to determine whether normal pigmented cells within the eye (melanocytes and retinal pigment epithelial cells) and cultured cells derived from malignant ocular melanomas express the MAGE genes that encode tumor antigens that are recognized by specific CD8+cytotoxic T lymphocytes. In the present series of experiments, we examined MAGE expression in cultured ocular melanoma cells obtained from a group of 17 ocular melanoma patients. Normal ocular melanocytes and retinal pigment epithelial cells were recovered and cultured from eyes enucleated for trauma. MAGE gene expression was determined using reverse transcription- polymerase chain reaction specific for either MAGE-1, -2, or -3. Our results demonstrate that MAGE-1, MAGE-2, and MAGE-3 genes are transcribed in primary ocular melanoma cell lines and are detected in cells recovered from 41, 53, and 53% of the patients examined, respectively. Normal choroidal melanocytes and retinal pigment epithelial cells did not express MAGE genes. We conclude that cultured ocular melanoma cell lines express MAGE-1, MAGE-2, and MAGE-3 genes

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Dendritic cells (DC) are potent professional antigen-presenting cells that can activate naive T lymphocytes and initiate cellular immune responses. As adjuvants, DC may be useful in enhancing the immunogenicity of tumor antigens and mediating tumor regression. Endogenous expression of antigen by DC offers the potential advantage of allowing prolonged constitutive presentation of endogenously processed epitopes and exploitation of multiple restriction elements for the presentation of the same antigen. In this report, we show that human DC are (a) capable of infection by recombinant poxviruses encoding melanoma-associated antigen (MAA) genes and (b) capable of efficiently processing and presenting these MAA to cytotoxic T cells. In 6/6 HLA A*0201-expressing melanoma patients tested, the virally driven expression of MART-1/Melan A MAA by DC was sufficient to generate CD8+ T lymphocytes that could recognize naturally processed epitopes on tumor cells. In most cases, specific anti-MART-1 reactivity could be detected after a single stimulation. Analysis of epitope dominance revealed that the amino acid sequence recognized by these cytotoxic T lymphocytes (CTL) corresponded to the MART-127_35 residues previously shown to be most commonly recognized by cytotoxic T lymphocytes expanded from metastatic melanoma lesions. These data show that the virally driven expression of MAA by DC can be exploited for the efficient induction of clinically relevant cytotoxic T-cell responses. This has clinical implications for active immunization therapy, and currently vaccine trials have been proposed for patients with metastatic melanoma

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Intrathymic inoculation of the radiation leukemia virus (RadLV) into C57BL/6 mice induces thymic lymphomas after 4—6 months. During premalignant latency, a population of RadLV-infected prelymphoma (PL) cells (whose survival is dependent on autostimulation with IL-4) persists in the thymus. PL cells explanted from RadLV-inoculated mice can be propagated in cultures containing IL-4, and in vitro growth of PL cells is effectively inhibited by anti-IL-4 antibodies. We subjected RadLV-inoculated mice to prophylactic treatment with anti-IL-4 antibodies and a virus-specific immunotoxin (IT). Administration of IT delayed the onset of lymphoma but was not curative. Anti-IL-4 antibodies had a similar effect when administered at low doses. High doses of anti-IL-4, given 3—5 weeks after virus inoculation, provided complete protection against lymphoma. These results demonstrate the effectiveness of prophylactic intervention during premalignancy by using antagonists that restrain the growth of PL cells

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The administration of high-dose interleukin-2 (IL-2) causes tumor regression in 17-25% of patients with metastatic melanoma or renal cell carcinoma. Renal dysfunction is a common dose-limiting toxicity of IL-2 administration, limiting 26% of treatment cycles. We have conducted a prospective randomized trial to evaluate whether the prophylactic administration of low-dose dopamine (2 mg/kg/min) can minimize renal toxicity and thus affect the amount of IL-2 administered. Forty-two patients were randomly assigned to receive systemic high-dose IL-2 with standard supportive measures (group A = 21 patients) or with the addition of prophylactic dopamine (group B = 21 patients) at 2 mg/kg/min. For patients in group B, dopamine was instituted 1 h before the initiation of IL-2 administration and was discontinued 6-12 h after the maximum number of doses of IL-2 were given. There was no difference in the amount of IL-2 administered for each course of therapy for groups A and B. Despite differences in urine flow (milliliters per kilogram per day), fluid balance (liters per day), and overall weight gain, prophylactic low-dose dopamine did not significantly alter maximum plasma urea or creatinine levels in group B when compared with the control group (group A). The overall toxicity profile considering all grade 3 and 4 toxicities for patients in groups A and B was comparable. Thus, there is no evidence to support the routine use of prophylactic low-dose dopamine in patients receiving high-dose IL-2

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

A phase II trial was conducted in patients with metastatic renal cell carcinoma, to assess the clinical efficacy and immunoregulatory effects of continuous-infusion recombinant interleukin–2 (rIL-2) (9.0 X 106IU/m2/day on days 1-5,8-12,15-19, and 22-26) and subcutaneously administered recombinant human interferon-a2b (rHuIFNa2b) (10.0 X 106U/m2/day TIW). Thirty-six patients with metastatic renal cell carcinoma, performance status of 0-1, and measurable disease who had not received prior rIL–2, rHuIFNa2b, or chemotherapy were treated. Patients with CNS metastases, active infections, history of another malignancy within 3 years, and those requiring corticosteroids were ineligible. Cycles of rIL–2 and rHuIFNa2b were administered in the outpatient department every 6-8 weeks in stable or responding patients until patient tolerance or a complete response were reached. Doses were modified for grade III or IV toxicity. Ancillary studies included three-color immunocytometric analysis of peripheral blood lymphocytes, repetitive tumor biopsies for immunohistologic analysis of infiltrating cells and proliferative responses of tumor infiltrating lymphocytes, and preliminary studies of changes in peripheral blood T–lymphocyte signal transduction molecules [T–cell receptor (TCR)–£, p56lck, pSfyn]. Thirtysix eligible patients were treated, with 6 of 36 patients (17%, 95% confidence interval 6–33%) responding (3 complete response, 3 partial response). In two of the partial responders, and in an additional three patients with either minimal tumor regression (one patient) or stable disease (two patients), surgical removal of residual disease was undertaken. The median survival of all patients was 14 months. The toxicity of this regimen was severe, but outpatient administration was possible in most instances. Immunoregulatory effects on T-cell subsets included increases in various CD3+CD25±HLADr±subsets unrelated to response. Tumor biopsies before and/or during therapy were obtained in 17 patients, and no consistent alterations in the degree of T-lymphocyte or macrophage infiltrates could be detected. In a subset of patients, tumor infiltrating lymphocyte proliferative responses and levels of peripheral blood T–cell signal transduction molecules (TCR–£, p56lck, p59fyn) were investigated. Abnormalities were found in selected patients, which improved during rIL–2/rHuIFNa2b therapy. This cytokine combination produces tumor regression in selected patients with metastatic renal cell carcinoma. Surrogate immunologic markers associated with response were not identified; however, preliminary studies demonstrate investigation of immune defects and their reversal with cytokine therapy is possible

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

ABSTRACTSeventy-two patients with metastatic renal cell cancer were treated with the combination of high-dose interleukin-2 (IL2), interferon-alpha (IFNa), and lymphokine- activated killer cells (LAK). Seventeen patients were entered in a feasibility part of the study (protocol 1) and 55 in an efficacy part (protocol 2). Protocol 2 differed from protocol 1 in the addition of IFNa to the first 5 days of IL2 infusion. Each patient was planned to receive two induction cycles. IL2, 18 MIU/m2/day, was administered continuously i.v. on days 1-5, and IFNa, 5 MIU/m2/day (protocol 2), was administered i.m. on days 1-5, followed by three daily lymphaphereses on days 7-9. On day 12, treatment was resumed with IL2 and IFNa on days 12-15 and LAK reinfusions on days 12-14. In protocol 1, three complete (CR) and one partial (PR) responses were achieved (response rate 24%). The median duration of response and the median survival were 18.1 and 13.9 months, respectively. The 3-year survival was 35%. Of the 51 evaluable patients in protocol 2, 6 achieved a CR and 13 a PR (response rate 37%). The median duration of response was 11.1 months. The median survival was 16.9 months. The 3-year survival was 35%. There were three treatment-related deaths. Other severe toxicities included hypotension, cardiotoxicity, pulmonary edema, renal toxicity, and infectious complications. In the two induction cycles, only 54 and 42% of the planned doses could be administered. We conclude that the use of high-dose regimens of IL2 and IFNa is not warranted, unless we can define more accurately which patients may experience long-term survival as a result of treatment.

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:1524-9557    

出版商:OVID    

年代:1997

数据来源: OVID