Biomedical subjects

S A Rosenberg

Publications and source records attributed to S A Rosenberg.

At least 19 recordsLinked to original sources

PubMed2003

Biased epitope selection by recombinant vaccinia-virus (rVV)-infected mature or immature dendritic cells.

Recombinant expression vectors represent a powerful way to deliver whole antigens (Ags) for immunization. Sustained Ag expression in vector-infected dendritic cells (DC) combines Ag-specific stimulation with powerful costimulation and, simultaneously, through 'self-selection' of ad hoc epitopes broadens the scope of immunization beyond restrictions posed by individual patients' human leukocyte antigen (HLA) phenotype. In this study, therefore, we evaluated the efficiency of a recombinant vaccinia virus encoding the gp100/PMel17 melanoma Ag (rVV-gp100) to infect immature (iDC) or mature dendritic cells (mDC) derived from circulating mononuclear cells and the effect of infection on their status of maturation. In addition, we tested the ability of rVV-gp100-infected iDC and mDC to present the HLA-A*0201-associated gp100:209-217 epitope (g209). Irrespective of status of maturation, rVV-gp100 infection induced gp100 expression while only partially reversing the expression of some maturation markers. However, endogenous presentation of the wild-type g209 epitope was inefficient. The low efficiency was epitope-specific since infection of DC with rVV encoding a gp100 construct containing the modified gp100:209-217 (210M) (g209-2M) epitope characterized by high binding affinity for HLA-A*0201 restored efficient Ag presentation. Presentation of an HLA-class II-associated epitope and cytokine release by DC was not altered by rVV infection. Thus, Ag expression driven by rVV may be an efficient strategy for whole Ag delivery. However, since the effectiveness of Ag processing and presentation is subject to stringent HLA/epitope pairing, and for other yet undefined rules, the assumption that whole Ag delivery may circumvent HLA restriction is incorrect and recombinant expression vectors encoding well-characterized polyepitopic constructs may prove more effective.

Antigen Presentation↗

PubMed2001

Transduction of an IL-2 gene into human melanoma-reactive lymphocytes results in their continued growth in the absence of exogenous IL-2 and maintenance of specific antitumor activity.

IL-2-dependent activated cells undergo apoptotic death when IL-2 is withdrawn either in vitro or after in vivo cell transfer. To attempt to sustain their survival after IL-2 withdrawal, melanoma-reactive human T lymphocytes were retrovirally transduced with an exogenous human IL-2 gene. Transduced PBMC and cloned CD8+ T cells produced IL-2 and maintained viability after IL-2 withdrawal. Upon restimulation, IL-2 transductants proliferated in the absence of exogenous IL-2 and could be actively grown, and their survival could be maintained without added IL-2 for over 8 wk. PBMCs similarly transduced with a control vector did not produce IL-2 and failed to proliferate in the absence of IL-2. A CD8+ T cell clone, when transduced with an IL-2 gene, manifested the same phenotypes as PBMCs in the absence of exogenous IL-2. Furthermore, an Ab reactive with the alpha-chain of IL-2R complex reduced the viability mediated by IL-2 secretion of the IL-2 transductants. Moreover, transduction of an IL-2 gene did not affect the high degree of recognition and specificity of transductants against melanoma targets. These tumor-reactive IL-2 transductants may be valuable for in vitro studies and for improved adoptive transfer therapies for patients with metastatic melanoma.

Autocrine Communication↗

PubMed2001

Mining the melanosome for tumor vaccine targets: P.polypeptide is a novel tumor-associated antigen.

To identify novel, tumor-specific target antigens for vaccine development, we studied immune responses to P.polypeptide, an M(r) 110,000 integral melanosomal membrane protein associated with the Prader-Willi syndrome. Together with expressed sequence tag (EST) and serial analyses of gene expression (SAGE) library analyses, reverse transcription-PCR and Northern blotting verified that P.polypeptide expression was limited to melanoma and melanocytes. A single dominant epitope corresponding to positions 427-435 (IMLCLIAAV) was identified using allele-specific epitope forecasting combined with work in HLA-A*0201/K(b) transgenic mice. This epitope was then used to generate de novo human P.polypeptide-specific CD8+ T cells capable of recognizing P.polypeptide expressing human tumor cell lines in an HLA-A*0201-restricted fashion. Thus, P.polypeptide may be valuable in the creation of novel therapeutic anticancer vaccines.

Animals↗

PubMed2001

Factors associated with response to high-dose interleukin-2 in patients with metastatic melanoma.

PURPOSE: The present study attempted to identify characteristics that correlated with clinical response to interleukin (IL)-2 therapy in patients with metastatic melanoma. PATIENTS AND METHODS: We retrospectively evaluated laboratory and clinical characteristics of 374 consecutive patients with metastatic melanoma treated with high-dose intravenous bolus IL-2 (720,000 IU/kg) from July 1, 1988, to December 31, 1999, at the Surgery Branch of the National Cancer Institute. RESULTS: The overall objective response rate was 15.5%. Pretreatment parameters such as patient demographics, laboratory values, and prior therapy did not correlate with response; however, 53.6% of patients with only subcutaneous and/or cutaneous metastases responded, compared with 12.4% of patients with disease at other sites (P2 =.000001). During therapy, patients who were responders tended to have received more doses during course 1 (16.2 +/- 0.3 doses v 14.5 +/- 0.2 doses; P2 =.0095); however, when limited to patients who were able to complete both cycles of course 1, there was no statistically significant difference (P2 =.27). Responders had a higher maximum lymphocyte count immediately after therapy compared with nonresponders (P2 =.0026). The development of abnormal thyroid function tests and vitiligo after therapy was associated with response (thyroid-stimulating hormone, P2 =.01; free T4, P2 =.0049; vitiligo, P2 < 10(-6)), although thyroid dysfunction may have been related more to the length of IL-2 therapy than to response. CONCLUSION: The presence of metastases only to subcutaneous and/or cutaneous sites, lymphocytosis immediately after treatment, and long-term immunologic side effects, especially vitiligo, were associated with antitumor response to IL-2 therapy.

Adolescent↗

PubMed2001

Short-term kinetics of tumor antigen expression in response to vaccination.

The melanoma patient's immune response to tumor has been extensively studied. Yet, the frequently observed coexistence of tumor-associated Ag (TAA)-specific T cells with their target cells in vivo remains unexplained. Loss of TAA expression might contribute to this paradox. We studied TAA expression in metastases by obtaining fine-needle aspirations from 52 tumor lesions in 30 patients with melanoma before and soon after immunotherapy. Limitations due to low amounts of starting material were overcome with a high fidelity antisense RNA amplification method. TAA expression was measured by quantitative real-time PCR of anti-sense RNA. Decrease in gp100/Pmel-17 TAA preceded tumor disappearance in several instances and could be best explained by immune selection because most patients had received gp100/Pmel-17-specific vaccination. Conversely, immune selection was absent in nonregressing lesions. These observations suggest that vaccination, when successful, triggers a broad inflammatory reaction that can lead to tumor destruction despite immune selection. Additionally, lack of clinical response might be attributed to lack of this initiating event rather than immune escape. This study provides an insight into the natural history of tumors and defines a strategy for the characterization of gene expression in tumors during therapy.

Adult↗

PubMed2001

Progress in human tumour immunology and immunotherapy.

Studies of the administration of interleukin-2 to patients with metastatic melanoma or kidney cancer have shown that immunological manipulations can mediate the durable regression of metastatic cancer. The molecular identification of cancer antigens has opened new possibilities for the development of effective immunotherapies for patients with cancer. Clinical studies using immunization with peptides derived from cancer antigens have shown that high levels of lymphocytes with anti-tumour activity can be raised in cancer-bearing patients. Highly avid anti-tumour lymphocytes can be isolated from immunized patients and grown in vitro for use in cell-transfer therapies. Current studies are aimed at understanding the mechanisms that enable the cancer to escape from immune attack.

Antigens, Neoplasm↗

PubMed2001

Kinetics of TCR use in response to repeated epitope-specific immunization.

Selection of T cell-directed immunization strategies is based extensively on discordant information derived from preclinical models. We characterized the kinetics of T cell selection in response to repeated antigenic challenge. By enumerating with epitope/HLA tetrameric complexes (tHLA) vaccine-elicited T cell precursor frequencies (Tc-pf) in melanoma patients exposed to the modified gp100 epitope gp100:209-217 (g209-2M) we observed in most patients that the Tc-pf increased with number of immunizations. One patient's kinetics were further characterized. Dissociation kinetics of g209-2M/tHLA suggested enrichment of T cell effector populations expressing TCR with progressively higher affinity. Furthermore, vaccine-elicited T cells maintained the ability to express IFN-gamma ex vivo and proliferate in vitro. Thus, repeated exposure to immunogenic peptides benefited immune competence. These results provide a rationale for immunization strategies.

Cancer Vaccines↗

PubMed2001

CD4(+) T cell recognition of MHC class II-restricted epitopes from NY-ESO-1 presented by a prevalent HLA DP4 allele: association with NY-ESO-1 antibody production.

NY-ESO-1 is a tumor-specific shared antigen with distinctive immunogenicity. Both CD8(+) T cells and class-switched Ab responses have been detected from patients with cancer. In this study, a CD4(+) T cell line was generated from peripheral blood mononuclear cells of a melanoma patient and was shown to recognize NY-ESO-1 peptides presented by HLA-DP4, a dominant MHC class II allele expressed in 43--70% of Caucasians. The ESO p157--170 peptide containing the core region of DP4-restricted T cell epitope was present in a number of tumor cell lines tested and found to be recognized by both CD4(+) T cells as well as HLA-A2-restricted CD8(+) T cells. Thus, the ESO p157--170 epitope represents a potential candidate for cancer vaccines aimed at generating both CD4(+) and CD8(+) T cell responses. More importantly, 16 of 17 melanoma patients who developed Ab against NY-ESO-1 were found to be HLA-DP4-positive. CD4(+) T cells specific for the NY-ESO-1 epitopes were generated from 5 of 6 melanoma patients with NY-ESO-1 Ab. In contrast, no specific DP4-restricted T cells were generated from two patients without detectable NY-ESO-1 Ab. These results suggested that NY-ESO-1-specific DP4-restricted CD4(+) T cells were closely associated with NY-ESO-1 Ab observed in melanoma patients and might play an important role in providing help for activating B cells for NY-ESO-1-specific Ab production.

Alleles↗

PubMed2001

Use of an in vitro immunoselected tumor line to identify shared melanoma antigens recognized by HLA-A*0201-restricted T cells.

An immunoselected melanoma cell line that had lost expression of the dominant melanoma antigens MART-1 and gp100 was generated in an attempt to identify previously unknown tumor antigens. After repeated stimulation with the autologous immunoselected tumor line, a number of HLA-A*0201-restricted T-cell clones were established from the peripheral blood of a single melanoma patient. One T-cell clone (C-22) recognized 14 of 16 HLA-A2+ melanoma cell lines, as well as HLA-A2+ melanocytes but recognized neither HLA-A2+ fibroblasts nor autologous B cells. Screening of an autologous cDNA library resulted in the isolation of a transcript identical to an entry in the expressed sequence tag database. Northern blot analysis revealed that this gene was expressed in most melanoma cell lines and melanocytes but not in normal tissues. The peptide epitope (AMF-GREFCYA) recognized by clone C-22 was identified based on studies of the recognition of truncated cDNAs and the use of the consensus HLAA*0201 binding motif. A second T-cell clone (C-29) was found to recognize a new tyrosinase-related protein 2 epitope (455-463; YAIDLPVSV) in an HLA-A*0201-restricted manner. Together, these results provide additional targets that can be used for the development of immunotherapeutic protocols in HLA-A2+ melanoma patients and demonstrate the utility of immunoselected tumor lines for the identification of new melanoma antigens.

Amino Acid Sequence↗

PubMed2001

High-dose therapy and autologous bone marrow transplantation for follicular lymphoma in first complete or partial remission: results of a phase II clinical trial.

Advanced stage follicular small cleaved and mixed cell lymphoma is characterized by relapse from remission and survival ranging from 6 to 12 years. Because young patients have the greatest compromise in longevity, the efficacy and toxicity of high-dose radiochemotherapy and bone marrow transplantation after conventional chemotherapy was evaluated in a prospective phase II clinical trial. Thirty-seven patients in a minimal disease state after conventional chemotherapy received fractionated total body irradiation and high-dose etoposide and cyclophosphamide, followed by purged autologous bone marrow. A reference sample of 188 patients of similar age, stage, and histology managed at this institution before 1988 was identified for comparison of patient characteristics and outcomes. Compared with reference patients, transplant recipients had a higher tumor burden at diagnosis. With a median follow-up of 6.5 years, the estimated 10-year survival after transplantation was 86%. There was a single lymphoma death yielding a 10-year disease-specific survival of 97%. There were 2 early transplant-related deaths and 2 late acute leukemia deaths. Ten patients relapsed, one with microscopic disease only. High tumor burden at diagnosis and incomplete response to chemotherapy adversely influenced survival in the reference but not in the transplanted patients. The estimated risk of death of 14% and relapse of 30% at 10 years in our transplanted follicular lymphoma patients, the majority of whom had high tumor burdens, compares favorably with our observations in appropriately matched reference patients.

Actuarial Analysis↗

PubMed2001

Progress in the development of immunotherapy for the treatment of patients with cancer.

Several recent developments have hallmarked progress in tumour immunology and immunotherapy. The use of interleukin-2 (IL-2) in cancer patients demonstrated that an immunological manipulation was capable of mediating the regression of established growing cancers in humans. The identification of the genes encoding cancer antigens and the development of means for effectively immunizing patients against these antigens has opened important new avenues of exploration for the development of effective active and cell-transfer immunotherapies for patients with cancer.

Antigens, Neoplasm↗

PubMed2001

Lack of retroperitoneal lymphadenopathy predicts survival of patients with metastatic renal cell carcinoma.

PURPOSE: Patients with metastatic renal cell carcinoma have a reported 5-year survival of 0% to 20%. The ability to predict which patients would benefit from nephrectomy and interleukin-2 (IL-2) therapy before any treatment is initiated would be useful for maximizing the advantage of therapy and improving the quality of life. MATERIALS AND METHODS: A retrospective analysis of the x-rays and charts of patients treated at the National Institutes of Health Surgery Branch between 1985 and 1996, who presented with metastatic renal cancer beyond the locoregional area and the primary tumor in place, was performed. Preoperative computerized tomography or magnetic resonance imaging, or radiological reports if no scans were available, were used to obtain an estimate of the volume of retroperitoneal lymphadenopathy. Operative notes were used to evaluate whether all lymphadenopathy was resected or disease left in situ, or if any extrarenal resection, including venacavotomy, was performed. Mean survival rate was calculated from the time of nephrectomy to the time of death or last clinical followup. If patients received IL-2 therapy, the response to treatment was recorded. Mean survival and response rate for IL-2 were compared among patients in 3 separate analyses. Patients without preoperatively detected lymphadenopathy were compared with those with at least 1 cm.3 retroperitoneal lymphadenopathy. Also, the patients who had detectable lymphadenopathy were divided into subgroups consisting of all resected, incompletely resected, unresectable and unknown if all disease was resected. Each subgroup was compared with patients without detectable preoperative lymphadenopathy. Patients with less than were compared to those with greater than 50 cm.3 retroperitoneal lymphadenopathy. Patients undergoing extrarenal resection at nephrectomy (complex surgery) due to direct invasion of the tumor into another intra-abdominal organ were compared with those undergoing radical nephrectomy alone, regardless of lymph node status. Statistical analysis was done with the Mantel-Cox test for comparison of survival on Kaplan-Meier curves and with Fisher's exact test for response rates for IL-2. RESULTS: A total of 154 patients with metastatic renal cell carcinoma underwent cytoreductive nephrectomy as preparation for IL-2 based regimens. There were 82 patients with metastatic renal cell carcinoma and no preoperative retroperitoneal lymphadenopathy who survived longer (median 14.7 months) than the 72 with lymphadenopathy (median 8.5, p = 0.0004). Patients with incompletely resected, unresectable or an unknown volume resected had decreased survival compared to those with no retroperitoneal lymphadenopathy. A multivariate analysis of survival was performed evaluating the known prognostic indicators, performance status and tumor burden, as represented by the number of organs involved with metastases, and the new prognostic factor, lymphadenopathy. Lymphadenopathy was more closely associated with survival than performance status, and appeared to be a new prognostic variable. Patients with and without retroperitoneal lymphadenopathy at initial presentation had similar rates for treatment with IL-2 (54% for both groups). Of the 82 patients with no lymphadenopathy 11 (13%) had long-term survival greater than 5 years. Of the 6 complete responses to IL-2, 5 occurred in this group. Only 1 other patient with incompletely resected retroperitoneal lymphadenopathy survived longer than 5 years. No significant difference in survival was seen between patients who did or did not undergo complex surgery. CONCLUSIONS: Patients who presented with metastatic renal cancer and retroperitoneal lymphadenopathy had a shorter survival than those with no detectable retroperitoneal lymphadenopathy. It is warranted to continue to perform complex extrarenal resection during nephrectomy since no significant difference in the response rate for IL-2 or mean survival compared with those of patients undergoing nephrectomy alone is currently detectable.

Adult↗

PubMed2000

Expansion and characterization of T cells transduced with a chimeric receptor against ovarian cancer.

Adoptive immunotherapy with genetically modified T lymphocytes is being utilized in clinical trials for the treatment of a broad range of diseases including cancer and HIV infection. To improve on these treatments, and to better understand their mechanisms of action, it is necessary to develop techniques to generate large numbers of cells and characterize the functional heterogeneity of the cells produced. In this study, patient peripheral blood lymphocytes were transduced with a chimeric antigen receptor (MOv-gamma) derived from a mouse monoclonal antibody against folate-binding protein, which is overexpressed on many ovarian cancers. Thus, irrespective of their original specificity, normal human T lymphocytes were redirected to react against ovarian cancer cells. Lymphocytes from five patients were transduced and grown to large numbers, with a median expansion of more than 7000-fold. When proliferation was inadequate, the cells were expanded by stimulation utilizing anti-CD3, IL-2, and irradiated allogeneic PBMCs. The cells maintained their functional ability to recognize ovarian cancer over several months. Cloning of transduced cells was undertaken to determine the level of gene expression and function of individual cells making up the bulk population. Transduced CD4(+) and CD8(+) cell clones were isolated from the bulk and demonstrated antitumor activity. These clones had a diverse repertoire with respect to secretion of cytokines, and individual clones maintained their cytokine profile on subsequent expansion. These studies establish the feasibility of consistently generating large numbers of gene-modified tumor-reactive lymphocytes, with a stable and diverse cytokine repertoire, that could be utilized for patient treatment.

Antibodies, Monoclonal↗

PubMed2000

Real-time quantitative polymerase chain reaction assessment of immune reactivity in melanoma patients after tumor peptide vaccination.

BACKGROUND: Monitoring the immune response to epitope-specific vaccination in cancer patients is important for vaccine development. The traditional method, in which the in vitro sensitization of peripheral blood mononuclear cells (PBMCs) with epitope is compared before and after vaccination, is time-consuming and allows only a qualitative assessment of the response. We used a rapid, quantitative, real-time polymerase chain reaction (PCR) assay to directly measure the immune reactivity of patients' PBMCs to the vaccine epitope. METHODS: PBMCs were obtained from melanoma patients before and after two rounds of vaccination with either g209-2M, a peptide derived from melanoma protein gp100 (n = 24), or ESg209-2M, a modified version of this peptide (n = 20). PBMCs were tested for immune reactivity by assaying interferon gamma (IFN gamma) protein release after in vitro sensitization with the epitope or for IFN gamma messenger RNA expression by real-time PCR. A twofold or more increase in IFN gamma protein release or a 1.5-fold or more increase in IFN gamma transcript accumulation in PBMCs after vaccination was considered to be evidence of a specific response. Correlation between the two methods was tested by use of the Spearman correlation coefficient after the results were ranked as positive or negative. All statistical tests were two-sided. RESULTS: The results obtained with the two methods were strongly correlated (Spearman's rho = 0.72; P =.0006). The g209-2M and Esg209-2M peptides resulted in similar percentages of vaccine-specific reactivity in PBMCs after in vitro sensitization (63% and 65% of patients, respectively; Fisher's exact test P =.6 for comparison of the two groups). The PCR method could detect vaccine-specific reactivity in a subset of patients (38% and 35% of patients, respectively; Fisher's exact test P =.7 for comparison of the two groups). CONCLUSION: Vaccination induces circulating antitumor lymphocytes, albeit in low frequencies, capable of directly reacting with tumor antigen. PBMCs of vaccinated individuals can respond to a vaccine-specific stimulus in a direct assay that does not require prolonged in vitro manipulations.

CD8 Antigens↗

PubMed2000

Status of activation of circulating vaccine-elicited CD8+ T cells.

Selective blunting of the status of activation of circulating tumor-specific T cells was invoked to explain their paradoxical coexistence with unhampered tumor growth. By analogy, lack of tumor regression in the face of observable melanoma vaccine-induced T cell responses might be attributed to their status of activation. We enumerated with HLA-A*0201/peptide tetramers (tHLA) vaccine-elicited T cell precursor frequency directly in PBMC of patients with melanoma undergoing vaccination with the HLA-A*0201-associated gp100:209-217(210 M) epitope (g209-2 M). Furthermore, we tested by intracellular (IC)-FACS analysis and quantitative real-time PCR (qRT-PCR) the ability of postvaccination PBMC to produce cytokine in response to challenge with vaccine-related epitopes or vaccine-matched (HLA-A*0201) melanoma cells. Vaccine-induced enhancement of T cell precursor frequency could be detected with tHLA in PBMC from six of eight patients studied at frequencies ranging between 0.3 and 2.3% of the total CD8+ population. Stimulation with vaccine-related epitopes induced IFN-gamma expression detectable by IC-FACS or qRT-PCR, respectively, in five and six of these patients. Furthermore, down-regulation of tHLA staining was noted upon cognate stimulation that could be utilized as an additional marker of T cell responsiveness. Finally, we observed in six patients an enhancement of reactivity against vaccine-matched tumor targets that was partly independent of documented vaccine-specific immune responses. A strong correlation was noted between tHLA staining of postvaccination PBMC and IFN-gamma expression by the same samples upon vaccine-relevant stimulation and assessed either by IC-FACS or qRT-PCR. Thus, blunting of the status of T cell activation on itself cannot easily explain the lack of clinical responses observed with vaccination.

Antigen Presentation↗

PubMed2000

Identification of CD4+ T cell epitopes from NY-ESO-1 presented by HLA-DR molecules.

In previous studies, the shared cancer-testis Ag, NY-ESO-1, was demonstrated to be recognized by both Abs and CD8+ T cells. Gene expression of NY-ESO-1 was detected in many tumor types, including melanoma, breast, and lung cancers, but was not found in normal tissues, with the exception of testis. In this study, we describe the identification of MHC class II-restricted T cell epitopes from NY-ESO-1. Candidate CD4+ T cell peptides were first identified using HLA-DR4 transgenic mice immunized with the NY-ESO-1 protein. NY-ESO-1-specific CD4+ T cells were then generated from PBMC of a patient with melanoma stimulated with the candidate peptides in vitro. These CD4+ T cells recognized NY-ESO-1 peptides or protein pulsed on HLA-DR4+ EBV B cells, and also recognized tumor cells expressing HLA-DR4 and NY-ESO-1. A 10-mer peptide (VLLKEFTVSG) was recognized by CD4+ T cells. These studies provide new opportunities for developing more effective vaccine strategies by using tumor-specific CD4+ T cells. This approach may be applicable to the identification of CD4+ T cell epitopes from many known tumor Ags recognized by CD8+ T cells.

Amino Acid Sequence↗

PubMed2000

Threshold levels of gene expression of the melanoma antigen gp100 correlate with tumor cell recognition by cytotoxic T lymphocytes.

The level of expression of melanoma antigens (MA) may modulate the host immunologic response. Thus, the accurate measurement of MA expression may allow proper patient selection for antigen-specific therapies and yield important information for the evaluation of clinical results. In this study, we measured the absolute levels of MA messenger ribonucleic acid (mRNA) in tumor cell lines utilizing real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). mRNA levels of MART-1, gp100, tyrosinase, TRP-1 and TRP-2 melanoma differentiation antigens and MAGE-1, MAGE-3 and ESO-1 cancer testis (CT) antigens were compared in 24 early-passage (<5 passages in culture) and 12 archival melanoma cell lines. MA mRNA expression was extremely variable among cell lines, occasionally reaching levels comparable to ribosomal RNA (rRNA). gp100 and MART-1 mRNA levels correlated with protein expression measurement obtained by FACS analysis. More significantly, a threshold of gp100 mRNA expression required for T-cell stimulation and target-cell killing was identified. This threshold level corresponded to approximately 500 mRNA copies per 10(8) copies of rRNA. Our results suggest that the measurements of MA mRNA levels may yield useful information relevant to the interpretation of clinical outcome during antigen-specific treatments.

Antigens, Neoplasm↗

PubMed2000

A tumor-infiltrating lymphocyte from a melanoma metastasis with decreased expression of melanoma differentiation antigens recognizes MAGE-12.

Twenty separate tumor infiltrating lymphocyte (TIL) bulk cultures and a tumor cell line were originated simultaneously from a fine needle aspiration biopsy of a metastasis in a patient with melanoma (F001) previously immunized with the HLA-A*0201-associated gp100:209-217(210 M) peptide. None of the TIL recognized gp100. However, 12 recognized autologous (F001-MEL) and allogeneic melanoma cells expressing the HLA haplotype A*0201, B*0702, Cw*0702. Further characterization of F001-MEL demonstrated loss of gp100/PMel17, severely decreased expression of other melanoma differentiation Ags and retained expression of tumor-specific Ags. Transfection of HLA class I alleles into B*0702/Cw*0702-negative melanoma cell lines identified HLA-Cw*0702 as the restriction element for F001-TIL. A cDNA library from F001-MEL was used to transfect IFN-alpha-stimulated 293 human embryonal kidney (293-HEK) cells expressing HLA-Cw*0702. A 100-gene pool was identified that induced recognition of 293-HEK cells by F001-TIL. Subsequent cloning of the pool identified a cDNA sequence homologous, except for one amino acid (aa 187 D-->A), to MAGE-12. Among 25 peptide sequences from MAGE-12 with the HLA-Cw*0702 binding motif, MAGE-12:170-178 (VRIGHLYIL) induced IFN-gamma release by F001-TIL when pulsed on F001-EBV-B cells at concentrations as low as 10 pg/ml. Peptide sequences from MAGE-1, 2, 3, 4a, and 6 aligned to MAGE-12:170-178 were not recognized by F001-TIL. In summary a TIL recognizing a MAGE protein was developed from an HLA-A*0201 expressing tumor with strongly reduced expression of melanoma differentiation Ags. Persisting tumor-specific Ag expression maintained tumor immune competence suggesting that tumor-specific Ags/melanoma differentiation Ags may complement each other in the context of melanoma Ag-specific vaccination.

Alleles↗