Apoptotic death of CD8+ T lymphocytes after immunization: induction of a suppressive population of Mac-1+/Gr-1+ cells

Following an infection or immunization, a primary CD8+ T cell response generally rises then falls rapidly before giving rise to a "memory" response. When we immunized mice with recombinant viral immunogens optimized to enhance the lytic capability of CD8+ T cells, we measured a profound depression in Ag-specific effector function after early restimulation. Indeed, a "mirror image" cytolytic capability was observed: the most powerful immunogens, as measured by cytolytic capacity 6 days after immunization, elicited the weakest secondary immune response when evaluated following an additional 6 days after restimulation. To understand the mechanism of this suppression, we examined the fate of splenocytes immunized with a vaccinia virus encoding Ag and IL-2 then restimulated ex vivo. We found that these splenocytes underwent an apoptotic cell death, upon early restimulation, that was not dependent on the engagement of the FasR (CD95). Unlike previously described mechanisms of "propriocidal cell death" and "clonal exhaustion," the cell death we observed was not an inherent property of the CD8+ T cells but rather was due to a population of splenocytes that stained positive for both the Mac-1 and Gr-1 surface markers. Deletion of these cells in vitro or in vivo completely abrogated the observed suppression of cytolytic reactivity of Ag-specific CD8+ T cells. These observations could account for the apparent absence of Ag-specific immune responses after some current vaccination regimens employing powerful immunogens. Finally, our results may shed new light on a mechanism for the suppression of CD8+ T cell responses and its effect on vaccine efficacy and on immune memory.

Identification of a shared HLA-A*0201-restricted T-cell epitope from the melanoma antigen tyrosinase-related protein 2 (TRP2)

Tyrosinase-related protein 2 (TRP2) is a melanosomal enzyme expressed in most mammalian melanocytes and melanomas. This protein has been identified as a melanoma antigen recognized by tumor reactive CTLs derived from tumor infiltrating lymphocytes in the context of HLA-A31 and HLA-A33. The frequencies of these HLA-A alleles among melanoma patients in the United States is low (approximately 6% for HLA-A31 and approximately 2% for HLA-A33) compared with that of HLA-A*0201 (approximately 46%). Therefore, to extend significantly the use of TRP2-based immunotherapies for the treatment of patients with melanoma, we searched for new HLA-A*0201-restricted epitopes from this protein by screening TRP2-derived peptides for the induction of melanoma-reactive CTL. Fifty-one peptides were selected from TRP2 based on a permissive HLA-A*0201 binding motif, and the 21 peptides with the highest experimentally determined binding affinities were used to stimulate peripheral blood lymphocytes from HLA-A*0201+ melanoma patients in vitro. One peptide, TRP2(180-188) (SVYDFFVWL), induced CTLs from three of four patients that specifically recognized peptide-pulsed T2 cells, COS-7 cells expressing HLA-A*0201 and TRP2, and HLA-A2+ TRP2+ melanomas. TRP2(180-188) is identical to a previously identified TRP2 epitope recognized by murine melanoma-reactive CTLs in the context of H-2Kb. These results suggest that TRP2 may be useful for the development of murine tumor immunotherapy models and for the treatment of melanoma patients who are diverse in HLA expression.

Immunization with a peptide epitope (p369-377) from HER-2/neu leads to peptide-specific cytotoxic T lymphocytes that fail to recognize HER-2/neu+ tumors

The oncogene HER-2/neu is genetically amplified and overexpressed in a large number of human adenocarcinomas and has been implicated in the tumorigenic phenotype. Although it is a nonmutated self-protein, it is barely detectable in adult tissues, and immune responses toward it have been described in a number of patients. It is, thus, an attractive candidate antigen for the immunotherapy of cancer patients. HLA-A2+ patients with metastatic breast, ovarian, or colorectal adenocarcinomas that overexpressed HER-2/neu were immunized with the HLA-A2-binding epitope p369-377 (p369). Patients were treated by repeated immunization with 1 mg of p369 in Freund's incomplete adjuvant every 3 weeks. Peripheral blood mononuclear cells were collected prior to immunization and following two and four immunizations and were stimulated in vitro with peptide and assayed for peptide and tumor recognition. In three of four patients, peptide-specific CTLs were detected in post- but not preimmunization blood. These CTLs recognized peptide-pulsed target cells at peptide concentrations of > or =1 ng/ml yet failed to react with a panel of HLA-A2+ HER-2/neu+ tumor lines. In addition, infecting HLA-A2+ cells with recombinant vaccinia virus encoding HER-2/neu or up-regulating HLA-A2 with IFN-gamma in HER-2/neu+ cells also failed to confer reactivity by p369-reactive T-cells. A T-cell response to the HLA-A2 binding epitope p369 can be easily generated by immunizing patients with peptide in Freund's incomplete adjuvant. However, the CTLs failed to react with HER-2/neu+ tumor cells. Further studies are needed to determine whether and how HER-2 might serve as an antigen for tumor immunotherapy.

Functional dissociation between local and systemic immune response during anti-melanoma peptide vaccination

Peptide vaccination against tumor Ags can induce powerful systemic CTL responses. However, in the majority of patients, no tumor regression is noted. To study this discrepancy, we analyzed CTL reactivity in a melanoma patient (F001) vaccinated with g209-2M peptide, a single residue variant of gp100(209-217). G209/g209-2M-reactive CTL were identified in post- but not prevaccination PBL. Limiting dilution analysis identified one predominant CTL clone (C1-35), with TCR Vbeta6s2, recognizing g209/HLA-A*0201-expressing targets. Additionally, two autologous melanoma lines (F001TU-3 and -4) and 20 separate tumor-infiltrating lymphocyte cultures were generated from a fine needle aspirate of a metastatic lesion progressing after initial response to vaccination. Both F001TU did not express gp100 and were not recognized by C1-35. Loss of gp100 by F001TU correlated with a marked reduction of gp100 expression in the same metastatic lesion compared with prevaccination. Thus, ineffectiveness of C1-35 and tumor progression could be best explained by loss of target Ag expression. Interestingly, 12 of 20 tumor-infiltrating lymphocyte cultures recognized F001TU, but none demonstrated g209/g209-2M reactivity, suggesting a functional dissociation between systemic and local immune response. This study suggests that vaccination effects must be analyzed in the target tissue, rather than in the systemic circulation alone.

A breast and melanoma-shared tumor antigen: T cell responses to antigenic peptides translated from different open reading frames

Infusion of TIL586 along with IL-2 into the autologous patient with metastatic melanoma resulted in the objective regression of tumor. Here, we report that screening a cDNA library from the 586mel cell line using CTL clones derived from TIL586 resulted in the isolation of a gene, CAG-3 (cancer Ag gene 3). Sequence analysis revealed that CAG-3 encodes an open reading frame identical to NY-ESO-1, which was recently reported to be recognized by autologous serum from a patient with esophageal cancer. Thus, NY-ESO-1 appears to be an immune target for both Ab- and T cell-mediated responses. Significantly, NY-ESO-1-specific CTL clones were capable of recognizing two HLA-A31-positive fresh and cultured breast tumors. To our knowledge, this represents the first direct demonstration that tumor-specific CTL clones can recognize both breast and melanoma tumor cells. A 10-mer antigenic peptide ESO10-53 (ASGPGGGAPR) was identified from the normal open reading frame of NY-ESO-1 based on its ability to sensitize HLA-A31-positive target cells for cytokine release and specific lysis. Interestingly, two additional CTL clones that were sensitized with NY-ESO-1 recognized two overlapping antigenic peptides derived from an alternative open reading frame of the same gene. These findings indicate that CTLs simultaneously responded to two different gene products translated from the normal and alternative reading frames of the same gene. Understanding of this mechanism by which the alternative reading frame is translated may have important implications in tumor immunology.

Durability of complete responses in patients with metastatic cancer treated with high-dose interleukin-2: identification of the antigens mediating response

OBJECTIVE

To determine the durability of complete responses in patients with metastatic melanoma or renal cancer treated with high-dose bolus interleukin-2 (IL-2) as well as the factors associated with the development of a complete response and the antigens mediating clinical responses.

METHODS

A consecutive series of 409 patients with either metastatic melanoma or renal cancer who were treated with high-dose bolus IL-2 in the Surgery Branch, National Cancer Institute, between September 1985 and November 1996 have been analyzed with a median potential follow-up of 7.1 years. All patients were treated with 720,000 IU/kg administered by 15-minute intravenous infusions every 8 hours for up to 5 days as clinically tolerated per cycle. Two cycles constituted a treatment course. Tumor-infiltrating lymphocytes (TIL) from melanoma patients were used to clone the genes encoding the tumor antigens responsible for clinical responsiveness.

RESULTS

Thirty-three of 409 (8.1%) patients treated with high-dose bolus IL-2 achieved a complete response and 37 (9%) achieved a partial response. Complete regression was seen in 6.6% and 9.3% of patients with metastatic melanoma and renal cancer, respectively. Twenty-seven of these 33 completely responding patients (82%) remain in ongoing continuous complete response from 39 to more than 148 months from the onset of treatment. Tumor regressions were seen at virtually all organ sites. The absence of prior treatment with immunotherapy, the total dose of IL-2 administered, and the maximal rebound lymphocytosis after cessation of IL-2 correlated with achieving a complete response. Expression cloning techniques have identified a series of tumor antigens that are recognized by TIL grown from resected melanomas. These antigens are mainly melanoma/ melanocyte differentiation antigens, although mutated intracellular proteins can also serve as antigens.

CONCLUSIONS

Treatment with high-dose bolus IL-2 mediates complete cancer regression in approximately 8% of patients with metastatic renal cancer and melanoma. The great majority of these patients will enter durable complete regressions and appear to be cured of their metastatic cancer. Thus, immunotherapy with high-dose bolus IL-2 should be considered as initial therapy for appropriately selected patients with metastatic melanoma and renal cell cancer. Identification of the tumor antigens mediating clinical response is opening new therapeutic possibilities for cancer treatment.

T cell-receptor V gene use by CD4+ melanoma-reactive clonal and oligoclonal T-cell lines

Tumor-reactive CD4+ T cells can be isolated and expanded from the peripheral blood and tumor lesions of patients with melanoma. In contrast to CD8+ T cells, little is known about the antigens recognized by these CD4+ T cells. As a consequence, little is known about the diversity of the T-cell receptor (TcR) use by melanoma-reactive CD4+ T cells. To address these questions, a panel of clonal or highly oligoclonal CD4+ T-cell lines was established from a patient with metastatic melanoma. A CD4+ tumor-infiltrating lymphocyte (TIL) line was established that was highly oligoclonal and recognized only autologous melanoma cells but not allogeneic melanomas, suggesting the expression of a mutated or uniquely expressed antigen by this melanoma. The antigen recognized by the CD4+ TILs could be presented by intact melanoma cells or by autologous Epstein-Barr virus (EBV) B cells pulsed with melanoma cell lysates. A panel of CD4+ clonal and highly oligoclonal T-cell lines was isolated form peripheral blood mononuclear cells (PBMC) from this patient; these were also reactive with autologous melanoma cells or tumor extracts pulsed on autologous EBV B cells. Despite their reactivity with the autologous melanoma, we found no evidence of restricted TcR V gene use, because all six T-cell lines recognized antigen via different TcR alpha/beta rearrangements. Furthermore, there were no conserved amino acids in the CDR3 regions of these TcRs, indicating that multiple TcR clonotypes could mediate recognition of a single unique major histocompatibility (MHC) complex class II restricted melanoma antigen or that multiple MHC class II restricted melanoma antigens are expressed by the melanoma.

Immunization of patients with melanoma peptide vaccines: immunologic assessment using the ELISPOT assay

PURPOSE

Interest in the development of antimelanoma peptide vaccines has been renewed by the identification of specific epitopes recognized by tumor-infiltrating lymphocytes that mediate tumor regression after adoptive transfer. The human leukocyte antigen (HLA)-A2*0201-restricted, nonmutated melanocyte differentiation antigen gp100 has multiple T-cell epitopes, of which three are recognized by most gp100-reactive tumor infiltrating lymphocytes. Synthetic peptides based on two of these epitopes, or modifications to improve HLA binding affinity, were used individually to vaccinate patients with metastatic melanoma. The purpose of this study was to evaluate the success of the vaccinations, as determined by the results of enzyme-linked immunospot (ELISPOT) tests of individual immune cells.

PATIENTS AND METHODS

The ELISPOT assay was used to measure the immunologic reactivity of peripheral blood lymphocytes from patients with metastatic melanoma before and after vaccination with gp100 peptides mixed with incomplete Freund's adjuvant. The peptides were g209 (ITDQVPFSV), g280 (YLEPGPVTA), modified g209 (g209-2M: IMDQVPFSV) or modified g280 (g280-9V: YLEPGPVTV) peptide. The patients' lymphocytes were tested by use of an ELISPOT assay for their ability to secrete interferon gamma with and without 12 days of in vitro sensitization with peptide.

RESULTS

Patients were successfully vaccinated by gp100 peptides, as judged by the ELISPOT assays. Restimulation of the patients' lymphocytes in vitro with peptide for 12 days before the ELISPOT assay significantly amplified the immune activity. Increased immune activity after vaccination was specific for the immunizing peptide or its altered form, was major histocompatibility complex restricted, and was apparent against HLA-A2+, gp100+ melanoma cell lines and against T2 cells pulsed with the appropriate synthetic peptides. In general, the frequency of immune T cells was 10 to 100-fold higher in ELISPOT assays against peptide-pulsed T2 cells than against melanoma cell lines. Judged by the ELISPOT assays, vaccination was successful in six of seven patients injected with g209-2M when tested against g209-2M peptide and in five of these seven patients when tested against the native g209 peptide. Vaccination was also successful in five of six patients injected with g209, one of three patients injected with g280-9V, and four of seven patients injected with g280. Even without peptide restimulation in vitro before the ELISPOT assay, the frequency of immune T cells among fresh peripheral blood mononuclear cells tested 3 weeks after a second vaccination with g209-2M peptide was elevated in four of six patients and was about 1/1000 of cells tested against the same peptide pulsed onto T2 cells.

DISCUSSION

Gp100 peptides were selected for vaccine development because they are epitopes recognized by tumor-infiltrating lymphocytes that are associated with tumor regression after adoptive immunotherapy in patients with metastatic melanoma. In the present study, most of the patients vaccinated with the gp209-2M peptide in incomplete Freund's adjuvant generated circulating antigen-specific immune T cells that could be detected by restimulation in vitro followed by an ELISPOT assay for individual cells secreting interferon gamma. The immune T cells reacted not only with the HLA-A2 restricted modified peptide but also with the native peptide and with melanoma cells that express gp100 and HLA-A2. Analysis of T-cell responses at the single cell level will be a valuable aid in assessing the effectiveness of melanoma vaccines and in determining optimal vaccine formulations and delivery.

Trends in the safety of high dose bolus interleukin-2 administration in patients with metastatic cancer

BACKGROUND

Administration of recombinant high dose interleukin-2 (IL-2) can mediate tumor regression in patients with metastatic melanoma and renal carcinoma. Significant trends in the safety of high dose IL-2 administration at a single institution over a 12-year study period were reviewed.

METHODS

A consecutive series of 1241 metastatic cancer patients treated with intravenous bolus infusions of IL-2 (720,000 IU/kg every 8 hours) were evaluated for the incidence of specific treatment-related toxicities, the maximum number of administered IL-2 doses, and objective response rates.

RESULTS

Significant decreases in the incidence of Grade 3 and/or Grade 4 toxicities were found when the initial group of 155 patients was compared with the final group: Grade 3/4 line sepsis (18% vs. 4%), Grade 3/4 diarrhea (92% vs. 12%), Grade 4 neuropsychiatric toxicity (19% vs. 8%), pulmonary intubations (12% vs. 3%), Grade 3/4 hypotension (81% vs. 31%), and Grade 4 cardiac ischemia (3% vs. 0%). No treatment-related deaths were noted in the final 809 patients. Laboratory abnormalities, such as increased creatinine, hyperbilirubinemia, and thrombocytopenia, were less severe, whereas percent weight gain remained stable over the 12-year period. The maximum number of administered IL-2 doses during the first cycle of therapy decreased from an initial median of 13 doses to 7 doses per first treatment cycle. No significant differences in overall and ongoing complete response rates to high dose bolus IL-2 were observed for melanoma patients (two-tailed P value = 0.40 and 1.0, respectively), or renal carcinoma patients (two-tailed P value = 0.92 and 0.89, respectively) over the study period.

CONCLUSIONS

Progressive reduction in morbidity and mortality was found with the systemic administration of high dose IL-2-based therapies over the 12-year study period. The improvement in safety most likely reflects the development of strategies to screen eligible patients, optimize therapeutic conditions, and judiciously terminate dosing when significant toxicities are noted. Despite these interventions, the overall and ongoing complete response rates for melanoma and renal carcinoma have not shown significant compromise. These trends suggest that high dose IL-2 can be safely administered to metastatic cancer patients under the current treatment guidelines and result in durable responses in a small subset of patients.

Development of a retrovirus-based complementary DNA expression system for the cloning of tumor antigens

A new retroviral system has been developed for the generation of a cDNA library and the functional cloning of tumor antigens. These retroviral vectors contain a cytomegalovirus promoter in the 5' long terminal repeat, an extended packaging signal for rapid production of high-titer retroviral particles, and many convenient cloning sites for cDNA library construction. The vesicular stomatitis virus G protein has been used to generate pseudotype retroviral particles to enable efficient viral infection. Using this system, viral titers in the range of 10(6) colony-forming units/ml could be generated routinely, and a high transduction efficiency in human primary cells, including fibroblasts, was achieved. In addition, a new procedure has been devised for screening a retrovirus-based cDNA library without a functional selection. The utility of this system was demonstrated by constructing a retrovirus-based cDNA library and re-isolating the NY-ESO-1 tumor antigen from a cDNA library using an antigen-specific CTL. This approach can facilitate the identification of novel tumor antigens recognized by T cells without knowledge of MHC class I restriction elements and is generally applicable for the isolation of any gene as long as a biological assay is available.

gp100/pmel 17 is a murine tumor rejection antigen: induction of "self"-reactive, tumoricidal T cells using high-affinity, altered peptide ligand

Many tumor-associated antigens are nonmutated, poorly immunogenic tissue differentiation antigens. Their weak immunogenicity may be due to "self"-tolerance. To induce autoreactive T cells, we studied immune responses to gp100/pmel 17, an antigen naturally expressed by both normal melanocytes and melanoma cells. Although a recombinant vaccinia virus (rVV) encoding the mouse homologue of gp100 was nonimmunogenic, immunization of normal C57BL/6 mice with the rVV encoding the human gp100 elicited a specific CD8(+) T cell response. These lymphocytes were cross-reactive with mgp100 in vitro and treated established B16 melanoma upon adoptive transfer. To understand the mechanism of the greater immunogenicity of the human version of gp100, we characterized a 9-amino acid (AA) epitope, restricted by H-2Db, that was recognized by the T cells. The ability to induce specific T cells with human but not mouse gp100 resulted from differences within the major histocompatibility complex (MHC) class I-restricted epitope and not from differences elsewhere in the molecule, as was evidenced by experiments in which mice were immunized with rVV containing minigenes encoding these epitopes. Although the human (hgp10025-33) and mouse (mgp10025-33) epitopes were homologous, differences in the three NH2-terminal AAs resulted in a 2-log increase in the ability of the human peptide to stabilize "empty" Db on RMA-S cells and a 3-log increase in its ability to trigger interferon gamma release by T cells. Thus, the fortuitous existence of a peptide homologue with significantly greater avidity for MHC class I resulted in the generation of self-reactive T cells. High-affinity, altered peptide ligands might be useful in the rational design of recombinant and synthetic vaccines that target tissue differentiation antigens expressed by tumors.

The use of melanosomal proteins in the immunotherapy of melanoma

Clinical observations in the interleukin (IL) 2-based immunotherapies suggest that T cells play a central role in the rejection of melanoma. Using cDNA expression cloning, we have isolated genes encoding melanoma antigens recognized by tumor-infiltrating T lymphocytes. These antigens are categorized as (a) melanocyte-specific melanosomal proteins (MART-1/melan A, gp100, tyrosinase, TRP-1, and TRP-2), (b) tumor-specific mutated proteins (beta-catenin), and (c) others (p15). A variety of mechanisms has been identified for the generation of T cell epitopes on tumor cells. Some of the HLA-A2 binding epitopes from the melanosomal antigens appear to be subdominant self-determinants with relatively low major histocompatibility complex binding affinity. The effectiveness of adoptive transfer into patients of cytotoxic T lymphocytes recognizing the melanosomal antigens, the significant correlation between vitiligo development and clinical response in patients receiving IL-2-based immunotherapies, and the sporadic tumor regressions observed in some patients following immunization with the MART-1 or gp100 peptides in incomplete Freund's adjuvant or recombinant viruses expressing the MART-1 antigen suggest that these epitopes may represent tumor rejection antigens. Phase I immunization trials using peptides or recombinant viruses containing genes encoding the melanosomal antigens MART-1 or gp100, with or without co-administration of cytokines such as IL-2, IL-12, or granulocyte-macrophage colony-stimulating factor, are being conducted in the Surgery Branch of the National Cancer Institute. These studies may demonstrate the feasibility of using melanosomal proteins for the immunotherapy of patients with melanoma.

Isolated hepatic perfusion with tumor necrosis factor and melphalan for unresectable cancers confined to the liver

PURPOSE

To evaluate the efficacy and systemic and regional toxicities of hyperthermic isolated hepatic perfusion (IHP) using tumor necrosis factor (TNF) and melphalan for the treatment of unresectable primary or metastatic cancers confined to the liver.

PATIENTS AND METHODS

Thirty-four patients (18 men and 16 women; mean age, 49 years) underwent a 60-minute hyperthermic (39.5 degrees to 40.0 degrees C) IHP performed by laparotomy that used TNF 1.0 mg and melphalan 1.5 mg/kg. Perfusion inflow was through the gastroduodenal artery and outflow was from a cannula positioned in an isolated segment of retrohepatic inferior vena cava (IVC). Infrahepatic IVC and portal venous blood flow were shunted to the axillary vein using an external venoveno bypass circuit. Complete vascular isolation of the liver was confirmed by an I-131-labelled human serum albumin monitoring technique.

RESULTS

There was no operative mortality. Seventy-five percent of patients had reversible grade III or IV (National Cancer Institute Common Toxicity Criteria) hepatic toxicity with one treatment-related mortality (3%) because of hepatic venoocclusive disease. In 33 assessable patients, the overall response rate was 75% (complete response, one patient [3%]; partial response, 26 patients [72%]). With a median potential follow-up of 15 months, the mean duration of response was 9 months (range, 2 to 30 months).

CONCLUSION

IHP with TNF and melphalan results in significant regression of bulky hepatic cancers confined to the liver in the majority of patients. Based on these initial results, further refinement of this treatment technique is warranted; perhaps by the combination of IHP with other regional treatment strategies to provide long-term control of unresectable cancers confined to liver.

Patterns of relapse and response to retreatment in patients with metastatic melanoma or renal cell carcinoma who responded to interleukin-2-based immunotherapy

PURPOSE

The purpose of this study was to examine the pattern of relapse and the treatment of relapse with either surgery or repeat immunotherapy in patients with metastatic melanoma or renal cell carcinoma who had previously responded to interleukin-2-based therapy.

PATIENTS AND METHODS

Over a 10-year period 1051 patients with metastatic melanoma or renal cell carcinoma were treated with interleukin-2-based immunotherapy at a single institution. One hundred fifty-nine patients who relapsed after an initial partial response or complete response to interleukin-2-based immunotherapy formed the study population for this retrospective review. Medical records, physical examination forms, and relevant radiographs were reviewed to determine response, relapse site(s), and response to treatment for relapse.

RESULTS

Relapse after an initial response to interleukin-2-based therapy occurred in 84 (80%) of 105 patients with metastatic melanoma and in 75 (70%) of 107 patients with metastatic renal cell carcinoma. Relapse after an initial partial response involved 71 (97%) of 73 patients with metastatic melanoma and 55 (86%) of 64 patients with metastatic renal cell carcinoma. The initial site(s) of relapse after a partial response involved a new site(s), old site(s), or both old and new sites with relatively even distribution. Relapse after an initial complete response occurred in 13 (41%) of 32 patients with metastatic melanoma and in 20 (47%) of 43 completely responding patients with metastatic renal cell carcinoma. Surprisingly, the initial site of relapse after a complete response involved only new sites of disease in 70% of patients. Retreatment of relapses with the same interleukin-2-based therapy originally used was effective in only one (2%) of 54 selected patients, but a different interleukin-2-based therapy in 35 patients resulted in five responders (a 14% secondary response rate). Most re-responders, however, responded to treatment with tumor-infiltrating lymphocytes and interleukin-2, and only one of 20 patients responded to retreatment with interleukin-2 alone. Surgical metastasectomy with therapeutic intent in 25 selected melanoma patients and in 31 selected renal cell cancer patients resulted in a 2-year progression-free survival of 18% in patients with metastatic melanoma and 37% in patients with metastatic renal cell carcinoma.

DISCUSSION

In patients with metastatic melanoma or renal cell carcinoma, tumor relapse was common after a partial response to an interleukin-2-based therapy and included previously identified sites of disease in most patients. Relapse after a complete response was less frequent and involved only new sites in a majority of patients. In selected patients who relapsed, repeat treatment with the same interleukin-2-based therapy that provided the initial response was rarely effective. However, with a different interleukin-2-based therapy, usually using tumor-infiltrating lymphocytes, repeat treatment induced secondary responses in some patients. In addition, salvage metastasectomy resulted in durable progression-free survival in selected patients.

Serum interleukin-6 levels in metastatic renal cell carcinoma before treatment with interleukin-2 correlates with paraneoplastic syndromes but not patient survival

PURPOSE

We sought to determine the frequency of interleukin-6 (IL-6) expression in renal cancer cell lines, the frequency of the detection of IL-6 in the serum of patients with metastatic renal cell carcinoma, whether serum IL-6 level correlates with the development of paraneoplastic syndromes and whether serum IL-6 level in patients with metastatic renal cancer correlates with response to treatment with interleukin-2 (IL-2) or patient survival.

MATERIALS AND METHODS

Conditioned media from 21 cell lines from 20 patients were examined for IL-6. We identified 2 matched groups of patients with metastatic renal cancer (30 responders and 29 nonresponders) to IL-2 based immunotherapy. Stored pretreatment serum specimens were evaluated for IL-6. Medical records were reviewed to determine the presence of paraneoplastic syndromes.

RESULTS

IL-6 was detected in 19 of 21 renal cancer cell lines (90%) obtained from 20 patients with metastatic renal cancer as well as in the serum of 33 of 59 patients (56%) with metastatic renal cell carcinoma. A significant association between serum IL-6 level and anemia (p = 0.0032), elevated platelet count (p = 0.01), decreased albumin (p = 0.034) and elevated alkaline phosphatase (p = 0.04) was found. A trend was noted of the association of increased serum IL-6 level and fever (p = 0.051). No correlation was found between pretreatment serum IL-6 level and survival or response to IL-2.

CONCLUSIONS

IL-6 was frequently secreted by renal cancer cell lines but it was only present in the serum of approximately half of the patients with metastatic renal cancer. Elevations of serum IL-6 were associated with paraneoplastic manifestations frequently seen in patients with renal cancer, including anemia, thrombocytosis, decreased albumin and elevations of alkaline phosphatase (Stauffer's syndrome). A weak relationship was noted between serum IL-6 level and fever but none was noted between that and survival or response to IL-2.

Immunologic and therapeutic evaluation of a synthetic peptide vaccine for the treatment of patients with metastatic melanoma

The cloning of the genes encoding cancer antigens has opened new possibilities for the treatment of patients with cancer. In this study, immunodominant peptides from the gp100 melanoma-associated antigen were identified, and a synthetic peptide, designed to increase binding to HLA-A2 molecules, was used as a cancer vaccine to treat patients with metastatic melanoma. On the basis of immunologic assays, 91% of patients could be successfully immunized with this synthetic peptide, and 13 of 31 patients (42%) receiving the peptide vaccine plus IL-2 had objective cancer responses, and four additional patients had mixed or minor responses. Synthetic peptide vaccines based on the genes encoding cancer antigens hold promise for the development of novel cancer immunotherapies.

Heterogeneous expression of melanoma-associated antigens and HLA-A2 in metastatic melanoma in vivo

MART-1/MelanA and Pmel17/gp100 are melanoma-associated antigens (MAAs) that can be recognized by tumor-infiltrating lymphocytes (TILs) capable of mediating successful adoptive therapy in vivo. Analysis of melanoma cell lines in vitro has demonstrated that heterogeneous antigen expression in the context of class I MHC is a significant co-factor in determining the recognition of melanoma targets by cytotoxic lymphocytes (CTLs). In this study, 217 specimens from 103 patients with metastatic melanoma were examined for the expression of MART-1/MelanA (monoclonal antibody [MAb] M27C10) and Pmel17/gp100 (HMB45 MAb) by immuno-histochemistry. Marked heterogeneity in the expression of both MAAs was confirmed by analysis of the percentage of positively staining tumor cells or the average intensity of tumor staining. We also noted heterogeneity of expression among multiple lesions taken from different anatomic sites within a patient. A dissociation was noted in the detection of MART-1 and gp100 in some lesions, with gp100 being undetectable in 24% of the lesions and MART-1 being undetectable in 11%. In several cases, loss of one MAA was not associated with loss of the other MAA, suggesting that MART-1 can represent a useful additional marker for the diagnosis of melanoma in gp100 (HMB45)-negative lesions. Of the 217 specimens, 155 were obtained from HLA-A*0201 patients, of which 6% were negative for HLA-A2, 8% were negative for MART-1/MelanA and 21% were negative for Pmel17/gp100. The potential significance of our findings is illustrated by a case study in which a patient with melanoma experienced rapid tumor progression in association with loss of either MAA or HLA expression in several lesions.

A T cell-independent antitumor response in mice with bone marrow cells retrovirally transduced with an antibody/Fc-gamma chain chimeric receptor gene recognizing a human ovarian cancer antigen

In order to treat common cancers with immunotherapy, chimeric receptors have been developed that combine the tumor specificity of antibodies with T-cell effector functions. Previously, we demonstrated that T cells transduced with a chimeric receptor gene against human ovarian cancer were able to recognize ovarian cancer cells in vitro and in vivo. We now report that recipients of bone marrow cells transduced with these genes exhibited significant antitumor activity in vivo. Moreover, in vivo depletion of T cells in reconstituted mice did not affect antitumor activity, suggesting that other immune cells expressing the chimeric receptor gene may play an important role in tumor rejection.

Stationary mechanical-assist technology for single-surgeon laparoscopic bilateral varicocelectomy

One potential detraction from the continued application of laparoscopy in the management of varicoceles is the requirement for a skilled assistant, which increases the cost of performing this surgery. This report describes the clinical application of a simple stationary mechanical-assist device to allow a single surgeon to perform bilateral varicocelectomies. The device is attached to the surgical table with a rotary adjusting stem-arm. A cross-mounted sidearm stretches over the patient and forms the attachment to the friction-jointed elbow and wrist attachment to the laparoscope, providing the range of motions similar to a human arm (shoulder, elbow, and wrist). By adjusting the tension at all three levels, changes of the laparoscopic camera portal are possible. Both of the surgeon's hands are then free to work through two operating trocars. The Laprotract arm (Minnesota Scientific, St. Paul, MN) costs $3000 and is autoclavable for quick reutilization. The average time needed to set up the device for bilateral varicocelectomy during eight cases was 2 minutes. The mean procedure time was 65.0 (+/-23.1) minutes, reflecting its ease of use. The electronic image obtained from the stationary mechanical assistant was always steady, and there was no inadvertent wandering from the surgical field. Statistical comparison with 63 open left and 22 open bilateral varicocelectomies during the same time period demonstrated no significant differences in the procedural times. Mechanical-assist technologies can facilitate laparoscopic bilateral varicocelectomies, allowing a single surgeon to perform this operation as quickly as left and bilateral open procedures.

Human tumor antigens recognized by T-cells

T-cells play an important role in in vivo tumor rejection in many animal tumor models and in human melanoma. Many human tumor antigens recognized by autologous T-cells have now been identified. These are found to be nonmutated and mutated peptides derived from various self proteins as well as viral proteins. A variety of mechanisms involved in generating these T-cell epitopes on growing cancers have also been identified. However, the role of these identified antigens remains to be evaluated. Passive or active immunotherapies using these identified tumor antigens are being conducted in many institutions. The results obtained from these clinical trials may give us better insight into the role of T-cell responses to each antigen in tumor rejection as well as the development of new antigen-specific immunotherapies for patients with cancer.

Recognition of an antigenic peptide derived from tyrosinase-related protein-2 by CTL in the context of HLA-A31 and -A33

Tumor-infiltrating lymphocytes (TILs) derived from tumor-bearing patients recognize tumor-associated Ags presented by MHC class I molecules. The infusion of TIL586 along with IL-2 into the autologous patient with metastatic melanoma resulted in the objective regression of tumor. Two T cell epitopes derived from tumor Ags, tyrosinase-related protein (TRP)-1 and TRP-2, were shown to be recognized by HLA-A31 restricted TIL586 and its T cell clones. In this study we tested the hypothesis that these two peptides can be recognized by CTL from non-HLA-A31 patients with melanoma. It was found that both peptides were capable of binding to HLA-A3, -A11, -A31, -A33, and -A68 of the HLA-A3 supertype. Importantly, we found that HLA-A33-positive TIL1244 and its T cell clones can recognize TRP197-205 presented by both HLA-A31 and -A33 molecules, suggesting that a single TCR can recognize peptide/A31 and peptide/A33 complexes. However, peptide titration experiments showed that the affinity of TCR receptor to peptide/A33 could be higher than that to the peptide/A31. These studies have important implications for the development of peptide-based cancer vaccines.

Use of recombinant poxviruses to stimulate anti-melanoma T cell reactivity

BACKGROUND

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 for enhancing immunogenicity and mediating tumor regression. Endogenous expression of antigen by DC could offer 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.

METHODS

DC were prepared from the peripheral blood of HLA A*0201 patients with metastatic melanoma in the presence of IL-4 (1000 IU/mL) and GMCSF (1000 IU/mL). Recombinant vaccinia and fowlpox viruses encoding the hMART-1 gene were constructed and used to infect DC. The efficiency of infection and expression of the MART-1 antigen were assessed by immunohistochemistry and intracellular FACS analyses. Cytotoxic lymphocytes (CTL) were generated by the stimulation of CD8+ T cells, with DC expressing the recombinant gene. Reactivity of the CTL was determined at weeks 1 and 2 by the amount of IFN-gamma released.

RESULTS

DC were infected with recombinant poxviruses and demonstrated specific melanoma antigen expression by immunohistochemistry, immunofluorescence, and intracellular FACS analysis. The expression by DC of MART-1 MAA after viral infection was sufficient to generate CD8+ T lymphocytes that recognized naturally processed epitopes on tumor cells in 10 of 11 patients.

CONCLUSIONS

Human DC are receptive to infection by recombinant poxviruses encoding MAA genes and are capable of efficiently processing and presenting these MAA to cytotoxic T cells. The potential advantage of this approach is the ability to present specific antigen independent of the identification of the epitope or the MHC restriction element. This strategy may be useful for the identification of relevant epitopes for a diverse number of HLA alleles and for active immunization in patients.

Randomized prospective study of the benefit of adjuvant radiation therapy in the treatment of soft tissue sarcomas of the extremity

PURPOSE

This randomized, prospective study assesses the impact of postoperative external-beam radiation therapy on local recurrence (LR), overall survival (OS), and quality of life after limb-sparing resection of extremity sarcomas.

PATIENTS AND METHODS

Patients with extremity tumors and a limb-sparing surgical option were randomized to receive or not receive postoperative adjuvant external-beam radiotherapy. Patients with high-grade sarcomas received postoperative adjuvant chemotherapy whereas patients with low-grade sarcomas or locally aggressive nonmalignant tumors were randomized after surgery alone.

RESULTS

Ninety-one patients with high-grade lesions were randomized; 47 to receive radiotherapy (XRT) and 44 to not receive XRT. With a median follow-up of 9.6 years, a highly significant decrease (P2 = .0028) in the probability of LR was seen with radiation, but no difference in OS was shown. Of 50 patients with low-grade lesions (24 randomized to resection alone and 26 to resection and postoperative XRT), there was also a lower probability of LR (P2 = .016) in patients receiving XRT, again, without a difference in OS. A concurrent quality-of-life study showed that extremity radiotherapy resulted in significantly worse limb strength, edema, and range of motion, but these deficits were often transient and had few measurable effects on activities of daily life or global quality of life.

CONCLUSION

This study indicates that although postoperative external-beam radiotherapy is highly effective in preventing LRs, selected patients with extremity soft tissue sarcoma who have a low risk of LR may not require adjuvant XRT after limb-sparing surgery (LSS).

Comparative analysis of the in vivo expression of tyrosinase, MART-1/Melan-A, and gp100 in metastatic melanoma lesions: implications for immunotherapy

A variety of human melanoma-associated antigens (MAA) have been identified that can be recognized by T lymphocytes in a major histocompatibility complex-restricted fashion. Among them, tyrosinase, MART-1/Melan- A, and gp100 are derived from nonmutated melanocyte lineage-specific antigens (Ag). These Ag can be recognized by CD8+ and, in the case of tyrosinase, CD4+ T cells. The in situ expression of these MAA may be a significant cofactor in determining the recognition of melanoma targets by Ag-specific T cells. In this study, we examined the patterns of expression of these MAA using immunohistochemical methods on 30 metastatic tumor deposits derived from 25 patients. MAA expression was heterogeneous among the 30 specimens and also within individual lesions. Of note, 23% of the samples examined failed to express the gp100 protein, and 17% of samples had no detectable expression of MART-1. In contrast, all lesions demonstrated some degree of tyrosinase expression even in cases where both gp100 and MART-1 were not detectable. In addition, 60% of samples (18 of 30) showed strong positivity for tyrosinase (> 75% of cells staining) compared with 40% for gp100 and 36% for MART-1. Currently, a number of experimental immunotherapies for melanoma are directed against the MAA tyrosinase, MART-1, and gp100. Although threshold levels of Ag required for T-cell recognition have not yet been defined, tumor-associated Ag expressed in high density, such as tyrosinase, may be better targets for future immunotherapy trials.