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D S Hoon

Publications and source records attributed to D S Hoon.

At least 55 records · Page 3Linked to original sources
PubMed1997

Recognition of gp43 tumor-associated antigen peptide by both HLA-A2 restricted CTL lines and antibodies from melanoma patients.

Previously, we detected a 43-kDa tumor-associated antigen (TAA) using the human monoclonal antibody L92, which recognizes the tetramer peptide KYQI. In the present study, cell lines of cytotoxic T lymphocytes (CTL) specific to the gp43 peptide (DLTMKYQIF) were established from peripheral blood lymphocytes (PBL) of melanoma patients. Patients' PBL (n = 326) of different HLA Class I types were assessed for gp43 CTL activity. CTL specific to gp43 peptide were generated only from HLA-A2 melanoma patients and not normal donors. gp43 CTL recognized gp43 peptide-pulsed autologous BLC and T2 HLA-A2 target cell lines. Furthermore, CTL lines were shown to kill both HLA-A2 autologous and HLA-A2 allogeneic melanoma cell lines, indicating that gp43 peptide can be processed endogenously and presented by melanoma cells as a common TAA. The gp43 CTL lines did not kill normal cells. Specific amino acids of the peptide were shown to be important determinants in stimulation and recognition of CTL. gp43 peptide, recognized by both antibodies and T cells of melanoma patients, is a novel TAA peptide that may play an important role in anti-tumor immunity in human.

Amino Acid Sequence↗
PubMed1997

Melanoma-associated antigens as messenger RNA detection markers for melanoma.

Melanoma is heterogeneous for its biological properties and melanoma-associated antigens (MAAs). This diversity is partially observed in the expression of the MAAs involved with the melanin synthesis pathway. We therefore developed a sensitive multimarker reverse transcription-PCR plus Southern blot assay using five MAAs as molecular markers to detect primary and metastatic melanoma cells. Melanoma cell lines, melanocytes (cultured), primary and metastatic malignant melanoma tissues, and blood from patients with American Joint Committee on Cancer stage I-IV melanoma were assessed for tyrosinase, tyrosinase-related proteins 1 and 2, Pmel 17, and MART-1/Melan-A. All of the MAA mRNA markers were expressed in 100% of melanoma cell lines and cultured melanocytes, 74% of primary and metastatic tumors (excluding tumor-draining lymph nodes), 43% of tumor-involved lymph nodes, and 43% of patients' bloods. Hypomelanotic melanoma tissues expressed a lower frequency of individual mRNA markers. Overall, at least one mRNA marker was expressed in more than 86% of specimens assayed. Normal tissue specimens from patients and blood from normal volunteer donors were negative for MAA mRNA expression. The multimarker MAA reverse transcription-PCR plus Southern blot analysis was more reliable and sensitive than a single-molecular marker assay for the detection of melanoma cells. This molecular assay can also provide information on MAA mRNA expression of metastatic melanoma cells that may assist in monitoring the therapeutic efficacy of active specific immunotherapy toward specific MAA-bearing melanomas.

Antigens, Neoplasm↗
PubMed1997

Induction of antibody response to human tumor antigens by gene therapy using a fusigenic viral liposome vaccine.

Development of effective cancer vaccines would help prevent and control tumor progression. A novel approach of immunizing against tumor antigens is in vivo gene vaccination. We have developed a fusigenic viral liposome vector using HVJ (hemagglutinating virus of Japan) and liposome to deliver human tumor antigen genes effectively to cells in vivo. Plasmids containing the human tumor antigen genes MAGE-1 and MAGE-3 were encapsulated in fusigenic viral liposomes and injected into mice intramuscularly. MAGE-1 and -3 recombinant proteins were used in Western blotting and affinity ELISA for assessment of antibody responses. Mice immunized with MAGE-1 and -3 gene vaccine individually were shown to produce anti-MAGE-1 and -3 IgG antibody responses respectively. Animals immunized with plasmid alone did not induce anti-MAGE-1 or -3 IgG responses. Antibody responses could be enhanced on reimmunization with the gene vaccines. Muscle biopsies taken after vaccine injection were verified to express gene-specific mRNA transcripts. Mice immunized with MAGE-1 or -3 gene vaccines were shown to induce antibodies that could cross-react with the respective recombinant proteins. This study demonstrates that in vivo immunization using HVJ-liposome containing human tumor antigen genes can effectively deliver and induce immune responses to the respective whole proteins.

Animals↗
PubMed1997

Molecular detection of tumor-associated antigens shared by human cutaneous melanomas and gliomas.

Both melanocytes and glial cells are derived embryologically from the neural ectoderm. Their malignant transformed counterparts, melanoma and glioma cells, respectively, may share common antigens. Numerous tumor-associated antigens have been identified in melanomas but only a few a gliomas. Using an established reverse transcriptase polymerase chain reaction plus Southern blot assay, we compared the mRNA expression of melanoma-associated antigens (MAAs) of melanomas to brain tumors primarily derived from glial cells. The MAAs studied included tyrosinase (Tyr), tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2), gp100, human melanoma antigen-encoding genes 1 and 3 (MAGE-1 and MAGE-3), and melanotransferrin (p97). Glioblastoma multiforme (n = 21), anaplastic astrocytoma (n = 3), ependymoma (n = 2), meningioma (n = 3), oligodendroglioma (n = 1), and melanoma (n = 12) tumor specimens were assayed for MAA mRNA expression. Glioblastoma multiforme, astrocytoma, and melanoma cell lines were also assayed. We observed that individual MAA mRNAs were expressed in these brain tumors and cell lines at varying frequencies. The melanogenesis-pathway-related MAAs Tyr, TRP-1, TRP-2, and gp100 mRNAs were also expressed at different levels in normal brain tissues but at a much lower frequency than in glioblastoma multiforme and melanoma. MAGE-1 and MAGE-3 mRNA were expressed in different types of tumor specimens and cell lines but never in normal brain tissue. Tumor antigen p97 was expressed in all types of tumors and also in normal brain tissues. These studies demonstrate that melanomas and primary brain tumors express common MAAs and could be exploited in patients with malignant glioma by active specific immunotherapy against these common MAAs.

Antigens, Neoplasm↗
PubMed1997

707-AP peptide recognized by human antibody induces human leukocyte antigen A2-restricted cytotoxic T lymphocyte killing of melanoma.

We recently identified a tumor-associated antigen that was recognized by human monoclonal antibody L94. The antibody-reactive 707-AP sequence RVAALARDAP, cloned from a melanoma cDNA library, was also found to be recognized by peripheral blood lymphocytes (PBLs) from melanoma patients. In this study, 707-AP was used to stimulate melanoma patients' PBLs for the establishment of peptide-specific CTL cell lines. CTL cell lines derived from 258 melanoma patients of different human leukocyte antigen (HLA)-A and HLA-B allele expressions were assessed by a 51Cr cytotoxicity assay against the peptide-pulsed autologous B lymphoblastoid cells and T2 HLA-A2 antigen-presenting cells and autologous and allogeneic melanoma cell lines. The analysis of 707-AP CTL activity demonstrated that only HLA-A2 patients' PBLs could be stimulated with 707-AP. 707-AP CTLs were able to specifically lyse HLA-A2 autologous and allogeneic melanoma cell lines. This verified the endogenous processing and presentation of 707-AP by melanoma cells. 707-AP CTL cytotoxicity against peptide-pulsed autologous HLA-A2 B lymphoblastoid cells and T2 HLA-A2 cells was also demonstrated. The killing activity of HLA-A2 707-AP CTL cell lines (CD8+ CD3+) was inhibited by anti-HLA class and anti-HLA-A2 monoclonal antibodies. The amino acid substitution or deletion analysis of the 707-AP sequence in CTL stimulation and recognition confirmed that position 2, amino acid V and position 9, amino acid A were essential. Both positions are known as supermotif anchors for HLA-A2 peptide sequences. Our studies demonstrated that 707-AP is a potent stimulator of CTLs that can induce peptide-specific HLA-A2 melanoma cell killing. The recognition of 707-AP by both antibody and CTLs suggests its potential significance as a peptide immunotherapeutic.

Amino Acid Sequence↗
PubMed1996

Preclinical development of a recombinant toxin containing circularly permuted interleukin 4 and truncated Pseudomonas exotoxin for therapy of malignant astrocytoma.

Effective treatment is lacking for malignant glioblastoma/astrocytoma. We have identified interleukin-4 receptors (IL-4R) on human malignant astrocytoma. We demonstrate that 16 of 21 surgical samples of high-grade astrocytoma and glioblastoma but not normal brain tissues expressed IL-4R as assessed by reverse transcriptase PCR. We further demonstrate that human malignant astrocytoma cell lines express high-affinity IL-4R. Using a chimeric protein composed of circularly permuted IL-4 and a truncated form of Pseudomonas exotoxin A, we observed that this toxin IL4(38-37)-PE38KDEL) is highly cytotoxic to IL-4R-bearing glioblastoma cells. Compared with a previously reported IL4-PE chimeric protein (IL-PE4E), IL4(38-37)-PE38KDEL bound with higher affinity and was 3-30-fold more cytotoxic to glioblastoma cell lines. Upon intrathecal administration in monkeys, high cerebrospinal fluid IL4(38-37)-PE38KDEL levels were achieved using 2- and 6-microg/kg doses without any central nervous system or other abnormalities. IL4(38-37)-PE38KDEL levels were not detectable in the serum of any monkey studied. When IL4(38-37)-PE38KDEL was injected into the right frontal cortex of rats, localized necrosis was observed at 1000-ng/ml doses but not at < or = 100-ng/ml doses. We conclude that by localized administration, nontoxic levels of IL4(38-37)-PE38KDEL can be achieved, which may have significant cytotoxic activity against malignant astrocytoma.

ADP Ribose Transferases↗
PubMed1996

Detection of metastatic breast cancer by beta-hCG polymerase chain reaction.

Reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of occult malignancies in breast cancer patients is evolving as a useful diagnostic tool. However, no reliable molecular mRNA markers are available. We developed an RT-PCR plus Southern blot assay using beta-hCG (beta-subunit of human chorionic gonadotropin) gene expression as a tumor marker for detection of breast malignancies metastatic to tumor-draining lymph nodes and blood. Breast carcinoma cell lines, primary breast malignancies and human placenta were used as positive controls for establishing the beta-hCG RT-PCR assay. Peripheral blood leukocytes (PBL) from normal volunteer donors, normal breast tissue and lymph nodes from cancer-free patients were used as negative controls. beta-hCG RT-PCR was used to assess tumor cell presence in PBL and tumor-draining axillary nodes from patients with AJCC stage I-IV breast cancer. The assay sensitivity and specificity were enhanced by restriction endonuclease digestion of an Sty I site of the RT-PCR cDNA product followed by Southern blot analysis. beta-hCG mRNA was expressed in all breast cancer cell lines and 80% of primary breast cancers; it was not expressed in negative controls. The assay reliably detected one cancer cell in > 10(7) PBL, with a sensitivity of 10(-5) microgram RNA. Eighty percent of PBL and 61% of tumor-draining axillary nodes from breast cancer patients expressed beta-hCG mRNA. The assay is a sensitive and specific method of identifying breast cancer cells in breast tissues, lymph nodes and blood.

Biomarkers, Tumor↗
PubMed1996

Interleukin 4 inhibits hepatocyte growth factor-induced invasion and migration of colon carcinomas.

Hepatocyte growth factor (HGF) is known to have a number of biological properties including promoting tumor progression of human carcinomas. Metastasis involves a number of events that are attributed to induction by paracrine factors such as HGF. Identification of natural inhibitors of these events would allow better control of tumor progression. Recently we demonstrated that interleukin 4 (IL-4) can regulate proliferation of various human carcinoma cell lines. In the present study, we used established human colon carcinoma cell lines and primary colon carcinoma cell cultures to determine if IL-4 could regulate HGF-induced cell proliferation and other events of tumor progression such as MMP (matrix metalloproteinases)-1, -2, and -9 production, cell migration and cell-matrix invasive activity. All colon carcinoma cell lines expressed HGF and IL-4 receptors. IL-4 significantly inhibited HGF-induced proliferation of one cell line. Cell-matrix invasion was significantly enhanced by HGF (0.1-10 ng/ml); IL-4 (1-10 U/ml) significantly inhibited HGF-induced invasion in a dose-dependent manner. IL-4 also inhibited HGF-induced cell-matrix invasion of metastatic colon carcinoma cells and HGF-induced cell migration. HGF enhanced MMP-1, -2, and -9 production by cell lines. This effect could be inhibited by IL-4. These findings indicate that IL-4 is a potent inhibitor of HGF-induced invasion and metastasis-related functions of human colon carcinoma cells.

Antigens, CD↗
PubMed1996

Detection of beta-human chorionic gonadotropin mRNA as a marker for cutaneous malignant melanoma.

The beta chain of human chorionic gonadotropin (hCG) hormone is produced by fetal cells, gonadal cell tumors and several types of non-gonadal carcinoma. hCG is composed of an alpha and a beta chain, the latter of which can be used to distinguish the molecule from other related gonadotropin hormones. Detection of beta-hCG mRNA transcripts can be potentially useful as a marker to identify tumor cells. We devised a highly specific and sensitive assay to detect the atavistic expression of beta-hCG in cutaneous melanoma by RT-PCR. Twenty-four melanoma cell lines and 43 melanoma biopsies were evaluated for beta-hCG mRNA expression. An RT-PCR assay was developed to specifically distinguish beta-hCG poly-A mRNA from other related gonadotropin beta chains. This was performed by endonuclease digestion of a unique Sty 1 site in the beta chain, followed by Southern blot analysis with a beta-hCG cDNA probe. Of the 24 melanoma cell lines analyzed, 18 expressed beta-hCG mRNA. Analysis of melanoma biopsy specimens revealed beta-hCG mRNA expression in 17/25 melanoma-positive TDLN, and in only 5/15 non-lymphoid melanoma metastases. Beta-hCG mRNA expression had a 53% correlation to tyrosinase mRNA, a predominant melanoma marker. Beta-hCG mRNA was not detected in normal donor PBL and normal lymph nodes. Detection of beta-hCG mRNA expression may be a useful molecular marker to define a subset of malignant melanoma.

Base Sequence↗
PubMed1995

Melanoma patients immunized with melanoma cell vaccine induce antibody responses to recombinant MAGE-1 antigen.

The MAGE-1 gene was recently characterized to encode an immunogenic tumor Ag on several types of human tumors, including melanoma. This Ag is expressed in a wide variety of human tumors and not in normal cells, except testicular tissue, as assessed through specific mRNA analysis. In this study we cloned the MAGE-1 gene exon 3 region from a colon carcinoma cell line and expressed it in Escherichia coli. The recombinant MAGE-1 protein was affinity purified. By using Western blot analysis, IgG and IgM anti-MAGE-1 Abs were detected in the sera of melanoma patients. Fifty-three patients immunized with a melanoma cell vaccine (MCV) were assessed for anti-MAGE-1 IgG responses by using a MAGE-1 Ag-specific ELISA. The MCV consisted of three melanoma cell lines that expressed MAGE-1. Comparisons of anti-MAGE-1 IgG response pre-MCV treatment with 12- to 16-wk post-MCV treatment were made. Fifty-seven percent of the patients immunized with the MCV showed significant enhancement of IgG response to recombinant MAGE-1 protein. Patients who responded had no particular HLA-A or -B allele expression pattern. Melanoma patients immunized with whole cell MCV containing MAGE-1 can enhance anti-MAGE-1 IgG Abs. Recombinant MAGE-1 protein can be used to assess patient response to MAGE-1 and will be investigated as a potential cancer vaccine against a wide variety of human tumors that express MAGE-1.

Amino Acid Sequence↗
PubMed1995

Cytotoxic T cell recognition of a human melanoma derived peptide with a carboxyl-terminal alanine-proline sequence.

Recently, we defined the antigenic epitope recognized by the human monoclonal antibody L94 to be a protein with a C-terminal sequence of alanine-proline (AP). An antigenic peptide no. 707 (RVAALARDAP), which was identified by the use of cDNA libraries of an antigen positive melanoma cell line M14, was evaluated for cellular immune responses in melanoma patients. PBMC from 16 of 19 melanoma patients were shown to lyse autologous B lymphoblastoid cell lines (BCL) pulsed with synthetic peptide no. 707 (hereafter no. 707). This specific cytotoxicity to the peptide significantly increased in 84% of melanoma patients after in vivo immunization with a melanoma cell vaccine (MCV). In contrast, peptide specific cytotoxicity was observed in only one of 19 normal volunteer donors. In vitro restimulation of MCV treated patients' PBMC with no. 707 augmented cytotoxicity against autologous no. 707-pulsed BCL. This cytotoxicity was specific to the C-terminal sequence AP, since the removal of C-terminal AP completely abolished the specific lysis. no. 707 restimulation of PBMC enhanced cytotoxicity against autologous melanomas. Autologous melanoma and peptide-pulsed BCL targets were lysed by CD8+CTL in a HLA class I-restricted manner. The strong cytotoxicity was obtained from patients of HLA A24. CTL lysis of autologous no. 707-pulsed BCL was partially blocked by unlabeled autologous melanomas in a cold target inhibition test. This suggested that the epitope identical or cross-reactive to no. 707 may be presented on the melanoma cell surface by HLA class I antigens. Our findings suggest that peptide no. 707 presented on human melanoma cells is recognized by CTL and that C-terminal AP plays a critical role in both antibody and T cell recognition.

Alanine↗
PubMed1995

Detection of occult melanoma cells in blood with a multiple-marker polymerase chain reaction assay.

PURPOSE: The objective of the study was to develop a sensitive multimarker polymerase chain reaction (PCR) assay to detect circulating melanoma cells in patient blood. The rationale was that malignant melanoma is heterogeneous in regards to antigen expression. PATIENTS AND METHODS: A PCR assay that uses four melanoma-associated gene markers (tyrosinase, p97, MUC18, and MAGE-3) was developed. Sensitivity and specificity of the PCR assay for individual markers were assessed using 10 melanoma cell lines and peripheral-blood lymphocytes (PBL) from 39 normal volunteers as controls. The assay's sensitivity and specificity were improved using nested primers and Southern blot analysis. Patients (N = 119) with American Joint Committee on Cancer (AJCC) stages I to IV disease were evaluated for circulating melanoma cells using the four gene markers under optimal conditions. RESULTS: All melanoma-associated gene markers were expressed in at least 80% of the melanoma lines, whereas 37 of 39 normal PBL tested negative for all markers; the remaining two PBL were positive for MUC18. Using four markers in the PCR assay was significantly better than using tyrosinase alone. There was a significant correlation between the number of positive PCR markers, AJCC stage of disease, and progression of disease. In all AJCC stages, there were more PCR-positive patients with disease than without disease. CONCLUSION: A multimarker PCR assay is more reliable and sensitive than a single-marker assay for detection of melanoma cells in blood of patients. This assay can provide important insight into tumor progression kinetics without major surgical or conventional radiologic diagnostic procedures.

Antigens, Neoplasm↗
PubMed1994

A decapeptide (Gln-Asp-Leu-Thr-Met-Lys-Tyr-Gln-Ile-Phe) from human melanoma is recognized by CTL in melanoma patients.

The decapeptide 810 (QDLTMKYQIF) contains the antigenic epitope (KYQI) recognized by human mAb L92. This sequence is found in a 43-kDa protein associated with human melanoma M14. We examined the expression of 810 in human cells and its involvement in the cellular immune responses of melanoma patients. Nineteen stage III melanoma patients and 19 normal donors were studied for their responses to 810. All patients were immunized in vivo with an allogeneic melanoma cell vaccine. PBMC cytotoxicity was tested on autologous EBV-transformed B lymphoblastoid cell lines (BCL) pulsed with 810 and autologous melanomas. Proliferative responses of PBMC to 810 were evaluated by using [3H]Tdr incorporation assays. Western blotting revealed that the 43-kDa protein was not specific to melanoma but was common to various cells. However, the percentage of cytotoxicity of PBMC against autologous 810-pulsed BCL was significantly greater in melanoma patients than in normal controls (p < 0.005). Cytotoxicity was increased after melanoma cell vaccine immunization in 15 patients (78%). Proliferative responses to 810 were observed only in melanoma patients and were enhanced in 12 patients (63%) after vaccination. Restimulation of PBMC from vaccinated patients with 810 increased cytotoxicity against both autologous 810-pulsed BCL and melanomas. These targets were lysed by CD8+ T lymphocytes in an HLA class I-restricted manner. HLA-A2 and -A11 seemed to serve as the 810-presenting molecule. Our findings indicate that 810 may function as an epitope for CTL on human melanoma and can be used as a vaccine.

Amino Acid Sequence↗
PubMed1994

Polyvalent melanoma cell vaccine induces delayed-type hypersensitivity and in vitro cellular immune response.

Patients with melanoma metastatic to distant sites or at high risk for recurrent melanoma have been treated with a polyvalent melanoma cell vaccine (MCV) in phase II protocols. We assessed in vivo and in vitro cell-mediated responses to MCV in 163 patients who had undergone surgical resection of American Joint Committee on Cancer stage III melanoma. During the first 4 months of vaccine immunotherapy, 135 patients (83%) responded by developing a positive delayed-type hypersensitivity reaction > or = 6 mm to MCV. In a mixed lymphocyte tumor cell reaction using peripheral blood lymphocytes, 35 of 42 patients (83%) showed a recall proliferative response to one or more of the three cell lines of MCV. There was a significant correlation between delayed-type hypersensitivity reaction and mixed lymphocyte tumor cell reaction (P = 0.013). After 4 months of MCV therapy, 8 of 11 patients had an increased mixed lymphocyte tumor cell reaction to autologous melanoma cells. During the first 4 months of vaccine therapy, 16 of 33 patients developed more than a 50% increase in cytotoxic T-cell activity against one of the cell lines of MCV. Overall survival was significantly prolonged in patients with a positive delayed-type hypersensitivity reaction (P = 0.0054) and/or increased cytotoxic T-cell activity (P = 0.02). These findings suggest that MCV induces specific T-cell responses which are correlated with clinical course; the data also suggest that some of these responses are directed against autologous melanomas and may play a major role in controlling the progression of melanoma.

Adolescent↗
PubMed1994

Interleukin 4 regulates G1 cell cycle progression in gastric carcinoma cells.

We have previously reported that interleukin 4 (IL-4) inhibits the growth of human gastric carcinoma cells. To investigate the mechanism for this inhibition we analyzed the effect of IL-4 on cell cycle progression of the IL-4-sensitive gastric carcinoma cell line, HTB-135. IL-4 significantly inhibited cell cycle G1-S-phase progression. To assess the postreceptor molecular events that transduced the negative-growth signals by IL-4, we analyzed the expression of cell cycle nuclear-regulating factors such as retinoblastoma gene product (Rbp), c-myc, c-myc protein (c-mycp), and cyclin D1 expression which are known to be regulators of G1-S-phase transition. IL-4 was found to induce an unphosphorylated form of Rbp within 24 h and significantly reduce the phosphorylated form at 48 h. The transition of Rbp to a hypophosphorylated form concurs with the decrease in c-myc gene expression and c-mycp. In addition, we demonstrated that IL-4 down-regulated p34cdc2, a kinase associated with Rbp phosphorylation and cyclin D1. Cyclin D1, considered as a critical nuclear regulatory factor of G0-G1 to S-phase transition was down-regulated 24 and 48 h post-IL-4 treatment as well. These studies suggest that IL-4 inhibits gastric cell proliferation by blocking cell cycle progression by down-regulating several key G0-G1 cell cycle nuclear-regulating factors.

Adenocarcinoma↗
PubMed1994

Characterization and augmentation of CD4+ cytotoxic T cell lines against melanoma.

Cytotoxic T cells have been implicated in the control of the progression of human melanoma. Most studies on human tumor T cell immunity have focused on the CD3+CD8+ cytotoxic T lymphocyte (CTL) phenotype; however, CD3+CD4+ CTL are important effector cells in other diseases and may also contribute to antimelanoma immunity. In this study we compared the functional activity of CD3+CD4+ and CD3+CD8+ CTL lines generated against autologous melanoma cells. CD8+ CTL had twofold higher cytotoxicity and serine esterase activity than CD4+ CTL. CD8+ CTL also were better binders to autologous melanoma cells. Binding of both CD4+ and CD8+ CTL to melanoma cells was significantly inhibited by ICAM-1 mAb. Interleukin-2 (IL-2) and IL-4 secretion was induced in both CD4+ and CD8+ CTL after stimulation by melanoma cells. A reverse transcriptase polymerase chain reaction performed on specific messenger RNA showed that both CD4+ and CD8+ CTL expressed IL-1, IL-2 and IL-4; CD4+ CTL also expressed interferon gamma (IFN). Both CTL phenotypes expressed receptors for IL-2 and IFN but only CD4+ CTL expressed the receptor for IL-4. Methods to augment CD4+ CTL growth were assessed using different combinations of cytokines. The combination of IL-2, IL-4 and IFN provided the optimal stimulation. Treatment of melanoma target cells with IL-4 and IFN enhanced CD4+ CTL recognition activity. CD4+ T cells are associated with antigen memory response and helper function, therefore activation of CD4+ CTL may be more beneficial with respect to long-term protective antimelanoma immunity.

Base Sequence↗
PubMed1993

Molecular cloning of a human monoclonal antibody reactive to ganglioside GM3 antigen on human cancers.

In this study we report the characterization of a human monoclonal antibody (HuMab), L612, that reacts with ganglioside GM3 and has therapeutic application for the treatment of human neoplasms, particularly melanoma. A permanent IgM-secreting Epstein-Barr virus-transformed B-cell line L612 was established. L612 HuMab bound specifically to neoplastic cell lines in culture and in tissue biopsy specimens such as melanoma, colon, breast, and lung cancer. The antibody did not bind to normal cells or biopsy tissue. HuMab L612 showed the highest reactivity to melanoma cells, particularly to those with high concentrations of GM3. Immunostaining on high-performance thin-layer chromatography plates demonstrated that L612 HuMab bound to GM3 purified from melanoma cells. Removal of the sialic acid from GM3 abolished antibody binding. HuMab L612 also reacted to GM4 purified from egg yolk, indicating that it recognizes an NeuAc alpha 2-3 galactose antigen determinant. HuMab L612 heavy and light chains were sequenced and determined to belong to the mu heavy chain variable subgroup III and kappa chain variable subgroup IV families, respectively. The studies indicate that the L612 HuMab has significant therapeutic potential for a wide variety of human cancers.

Adenocarcinoma↗