Biomedical subjects

R J Cote

Publications and source records attributed to R J Cote.

At least 73 records · Page 4Linked to original sources

PubMed1994

Antigen retrieval using pH 3.5 glycine-HCl buffer or urea solution for immunohistochemical localization of Ki-67.

A new antibody (MIB-1) has been described, permitting the demonstration of Ki-67 proliferation antigen in paraffin sections. However, satisfactory results were obtained only after subjecting tissue sections to microwave based antigen retrieval in citrate buffer solution. Other buffer solutions produce equivalent or better results and also permit use of the original Ki-67 antibody, which hitherto has been considered ineffective for paraffin sections.

Buffers↗

PubMed1993

Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.

Antigens, Neoplasm↗

PubMed1993

p53 nuclear protein accumulation correlates with mutations in the p53 gene, tumor grade, and stage in bladder cancer.

Seventy-three transitional cell carcinomas of the bladder were analyzed by immunohistochemistry for p53 nuclear accumulation, and the results were compared to mutations detected in the p53 gene by single strand conformational polymorphism analysis (SSCP) and DNA sequence analysis. Immunohistochemical studies were performed on formalin-fixed, paraffin-embedded tissue sections. A highly significant association between the presence of p53 mutations and p53 nuclear reactivity as detected by immunohistochemistry was found (P = 0.0001). Of 32 tumors that demonstrated p53 mutations by SSCP, 27 (84%) showed p53 nuclear reactivity. Of the five cases that did not demonstrate p53 nuclear reactivity, four had mutations in exon 5. However, of 41 tumors with no evidence of p53 mutation by molecular analysis, 12 (29%) showed p53 immunoreactivity. This indicates that immunohistochemical methods may be more sensitive than SSCP in detecting p53 mutations or that discordant cases represent tumors with accumulation of wild type p53 protein, without mutations at the p53 locus. Of the 15 tumors that were found to have mutations at exon 8, 13 demonstrated high-intensity homogeneous p53 nuclear reactivity by immunohistochemistry, and all mutations located at codon 280 demonstrated high-intensity homogeneous immunoreactivity. However, three of three tumors with exon 6 mutations demonstrated low-level p53 immunoreactivity, and four of six tumors with mutations in exon 5 showed no detectable p53 nuclear reactivity. This indicates that the heterogeneity of immunoreactivity observed when analyzing p53 nuclear accumulation may be related to the site of the p53 gene mutation. Information on tumor grade, stage, lymph node status, disease-free interval, and overall survival were available in 54 patients who had undergone cystectomy. A significant association was observed between p53 alterations (detected by immunohistochemistry and SSCP) and histological tumor grade (P = 0.003) and stage (P = 0.01). We conclude that the immunohistochemical detection of p53 nuclear accumulation in formalin-fixed, paraffin-embedded tissue is highly associated with mutations in the p53 gene; this association has now been demonstrated in a large number of tumors. The heterogeneity of p53 nuclear reactivity seems to be related to the site of mutation in the p53 gene. A small proportion of tumors with a p53 gene mutation do not demonstrate immunohistochemically detectable p53 nuclear accumulation. Furthermore, a small but substantial proportion of tumors demonstrate p53 nuclear reactivity but do not show detectable mutations in the p53 gene by SSCP. Finally, both grade and stage of bladder cancer are related to p53 alterations, detected by immunohistochemistry or molecular methods.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinoma, Transitional Cell↗

PubMed1993

Carcinomas of Bartholin's gland. Histogenesis and the etiological role of human papillomavirus.

In this study, we examine 10 primary carcinomas of Bartholin's gland, including seven squamous carcinomas, two adenoid cystic carcinomas, and one adenocarcinoma, as well as four non-neoplastic Bartholin's gland. Six of seven squamous cell carcinomas contained human papillomavirus (HPV) type 16 DNA detectable by the polymerase chain reaction; one of these demonstrated HPV type 16 by in situ hybridization. The two adenoid cystic carcinomas, the adenocarcinoma, and the non-neoplastic Bartholin's gland epithelium showed no evidence of HPV DNA by polymerase chain reaction or in situ hybridization. A panel of eight antibodies (Cam 5.2, B72.3, CEA, EMA, MCA, Lewis X, ER, and PR) demonstrate that the squamous, transition zone, duct, acinar, and myoepithelial cells or Bartholin's gland are antigenically distinct, and are similar to those reported in analogous areas of the uterine cervix. Squamous carcinoma and adenocarcinomas of Bartholin's gland are antigenically similar, and seem to arise from the transition zone of the Bartholin's gland duct. The origin of adenoid cystic carcinomas is more difficult to determine; it is distinct from squamous and adenocarcinomas and seems more likely to arise from myoepithelial cells. We conclude that adenocarcinoma and squamous cell carcinoma of Bartholin's gland arise in the transition zone of Bartholin's gland, which is similar to the transition zone of the uterine cervix. We also show that HPV is associated with Bartholin's gland carcinoma and may play a role in the genesis of malignancy.

Adult↗

PubMed1991

Genetic alterations of the p53 gene are a feature of malignant mesotheliomas.

A putative tumor suppressor gene, p53, has been shown to be altered in a variety of human tumor types. The primary mechanism of p53 inactivation is believed to be mutation of one allele followed by loss of the second allele. Malignant mesothelioma is a tumor that has been highly associated with exposure to asbestos fibers, which are known to cause chromosomal abnormalities in mesothelial cells. We have examined four mesothelioma cell lines for genetic abnormalities in p53. Cytogenetic analysis revealed that two of the four tumors had abnormalities (numerical and/or structural) of chromosome 17 (the locus of the p53 gene). Restriction fragment length polymorphism analysis using a chromosome 17p-specific probe (pYNZ22) revealed that two tumors had loss of heterozygosity in the region of 17p13. The relative level of p53 mRNA expression was examined by Northern analysis, with one tumor showing negligible expression of p53 mRNA. The complementary DNA of p53 was generated from the three tumors showing detectable mRNA expression, and the region between codons 70 and 319 was amplified by the polymerase chain reaction and sequenced. DNA single-base substitutions were detected in two of the tumor cell lines, each resulting in amino acid substitutions. One tumor had an arginine to histidine substitution at position 175, and one tumor had a glycine to aspartic acid substitution at position 245. The observed mutations took place in regions of high cross-species sequence homology, indicating that these regions may be functionally important. The correlation of chromosomal loss in 17p on the cytogenetic and molecular level along with p53 mRNA expression and DNA sequence data indicate that genetic alterations in p53 could be a feature of malignant mesotheliomas and may reveal an important role of asbestos fibers in tumor suppressor gene inactivation.

Blotting, Northern↗

PubMed1991

Sensitivity of immunocytochemical detection of breast cancer cells in human bone marrow.

We have previously shown that occult micrometastases can be detected in the bone marrow of breast cancer patients, at the time of initial treatment, using a panel of epithelial specific monoclonal antibodies indirectly labeled with fluorescein. These monoclonal antibodies permit us to detect cancer cells at at concentration of two/million normal bone marrow cells. Immunofluorescence carries the disadvantage that detailed morphological examination of detected cells cannot be accomplished. A modification of the alkaline phosphatase anti-alkaline phosphatase method has been used to detect cancer cells and to observe their morphology in human bone marrow. The sensitivity of this method has been examined using an established human metastatic breast cancer cell line (MCF-7) mixed with normal bone marrow cells at various dilutions from 400 cancer cells/10(6) marrow cells to 10 cancer cells/10(6) marrow cells. The number of immunocytochemically stained MCF-7 cells counted at each concentration was related to the concentration by a simple nonlinear statistical model. At a concentration of 10 cancer cells/10(6) bone marrow cells, the model shows that this method has the sensitivity to detect between four and six MCF-7 cells 95% of the time. Extrapolation, using this model, predicts that at the very low concentration of one cancer cell/10(6) marrow cells, there is a 95% chance of detecting the cancer cell. This assay may be a very sensitive method for detecting cancer cells in the bone marrow of breast cancer patients.

Antibodies, Monoclonal↗

PubMed1991

Prediction of early relapse in patients with operable breast cancer by detection of occult bone marrow micrometastases.

We used monoclonal antibodies to identify occult micrometastases in the bone marrow of 49 patients with operable (stage I and II) breast carcinoma. Follow-up (mean, 29 months; median, 30 months) revealed that 12 patients recurred. The presence of bone marrow micrometastases (BMM) was significantly associated with early recurrence (P less than .04). The estimated 2-year recurrence rate for patients with no BMM detected (BMM-) was 3%; in patients with BMM, the 2-year recurrence rate was 33%. When BMM and axillary lymph node (LN) status were combined, groups of patients at low risk (LN-, BMM-; 2-year recurrence rate, 0%) and high risk (LN+, BMM+; 2-year recurrence rate, 42%) for early recurrence were identified. Bone marrow tumor burden was related to early recurrence. Among patients with BMM, those who did not recur had on average fewer extrinsic cells in their marrow than those who recurred (15 v 43 cells, respectively). Multivariate analysis comparing BMM, LN+ versus LN-, and tumor size (less than or equal to 2 cm v greater than 2 cm) revealed no factor independently associated with early recurrence. Peripheral tumor burden of BMM (0 or less than 10 extrinsic cells v greater than or equal to 10 extrinsic cells) was the only independent predictor of early recurrence (P less than .003). In conjunction with conventional prognostic factors, particularly axillary LN status, evaluation for BMM might be used to stratify patients for adjuvant treatment programs. Because this pilot study involved few patients with short-term follow-up, the results should be interpreted with caution. The examination of bone marrow for micrometastases remains an experimental procedure; the clinical usefulness of the test will be established through larger studies with long-term follow-up.

Antibodies, Monoclonal↗

PubMed1990

Rhabdomyosarcoma of the liver associated with long-term oral contraceptive use. Possible role of estrogens in the genesis of embryologically distinct liver tumors.

We report a case of rhabdomyosarcoma arising in a 34-year-old woman with a 16-year history of oral contraceptive use. This is the first reported case of hepatic rhabdomyosarcoma associated with oral contraception. The tumor did not grossly or microscopically involve biliary structures or gall bladder. It was mostly comprised of undifferentiated spindle cells that were histologically similar to embryonal sarcoma. Foci of cells showing rhabdomyoblastic differentiation blended into poorly formed muscle bundles. No epithelial neoplasm was identified by either morphologic or immunohistochemical analysis. A review of the literature reveals that, although the incidence is low, mesenchymal neoplasms of the liver have been associated with oral contraceptive use. Furthermore, there is now evidence that a multipotential progenitor cell exists that can give rise to both epithelial and mesenchymal neoplasms. Thus, there may be a common precursor cell on which estrogens could act, and which could give rise to epithelial, mesenchymal, or mixed neoplasms. Finally, we suggest that embryonal sarcomas of the liver can undergo further differentiation to more well-defined mesencymal elements.

Actins↗

PubMed1990

Immunopathology of adrenal and renal cortical tumors. Coordinated change in antigen expression is associated with neoplastic conversion in the adrenal cortex.

A series of adrenal cortical adenomas (ACA) and carcinomas (ACC), as well as normal adrenal cortex have been studied by a panel of 11 antibodies to characterize antigenic changes that may distinguish these morphologically similar entities. Normal adrenal cortex and ACA express low-molecular weight cytokeratin intermediate filaments. However, none of the six primary or seven metastatic ACCs were found to express detectable levels of cytokeratins. In contrast, vimentin was seen in all ACCs studied and was heterogeneously expressed by ACAs. However, its expression was usually confined to stromal elements of the normal adrenal cortex. We conclude that adrenal cortical cells undergo characteristic changes in intermediate filament expression during the process of neoplastic conversion and malignant transformation. Undetectable expression of cytokeratins and strong expression of vimentin is associated with malignant adrenal cortical lesions. In addition, we examined the antigenic phenotype of a series of primary renal cell carcinomas (RCC). Renal cell carcinomas express cytokeratins, while ACCs do not. The majority of primary RCCs express Lewis blood group isoantigens (most commonly Lewis X), while ACAs and ACCs do not. The panel of antibodies described here may help to distinguish morphologically similar lesions of like histogenesis (ACAs vs. ACCs) and lesions of different histogenesis (adrenal vs. renal) on the basis of their composite antigenic phenotypes.

Adenoma↗

PubMed1990

Disseminated Pneumocystis carinii infection causing extrapulmonary organ failure: clinical, pathologic, and immunohistochemical analysis.

Pneumocystis carinii pneumonia is an important infection in the immunocompromised host, and the rate of symptomatic infections has risen dramatically with the advent of immunosuppressive therapies and infections with the human immunodeficiency virus (HIV). However, dissemination of P. carinii is thought to be an unusual event, and it is rarely suspected of causing extrapulmonary symptomatology. We have recently examined the cases of patients with acquired immunodeficiency syndrome (AIDS) who demonstrated at autopsy extrapulmonary infection with P. carinii. Three of these patients had widespread pneumocystosis, and in one patient dysfunction in several organs could be directly attributed to effects of P. carinii, which contributed to his death. The possible factors leading to dissemination of P. carinii are discussed. We also describe the use of a newly developed monoclonal antibody to P. carinii in detecting extrapulmonary infections.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Immunofluorescent monoclonal antibody detection of breast cancer in bone marrow: sensitivity in a model system.

We have previously shown that occult micrometastases can be detected in the bone marrow of breast cancer patients using a panel of epithelial specific monoclonal antibodies in an indirect immunofluorescent assay. The sensitivity of this assay has been examined using cells from an established human breast cancer cell line (MCF-7) mixed with normal bone marrow at various dilutions from 400 cancer cells/10(6) marrow cells (400:10(6] to 10:10(6). MCF-7 cells were detected at the lowest concentration studied, namely 10:10(6). The number of fluorescent labeled MCF-7 cells counted at each concentration was related to the concentration by a simple nonlinear statistical model. At the concentration of 10:10(6), the model shows that this technique has the sensitivity to detect between two and four MCF-7 cells 95% of the time. Moreover, by extrapolation, the model predicts that even at the very low concentration of 2:10(6), there is a 95% chance of detecting one cancer cell. Therefore, this assay may be a very sensitive method for detecting cancer cells in the bone marrow in vivo.

Antibodies, Monoclonal↗

PubMed1988

Tissue distribution and cellular location of the antigens recognized by human monoclonal antibodies 16.88 and 28A32.

Results from a previous study (M. V. Haspel et al., Cancer Res., 45: 3951-3961, 1985) indicated that it was possible to isolate a high proportion of human monoclonal antibodies reactive with cell surface, tumor-associated antigens when the hybridomas were obtained from fusions utilizing peripheral blood lymphocytes from patients immunized with autologous tumor cells. The assignment of membrane reactivity was made from immunoperoxidase studies which used air-dried, nonpermeabilized Cytospin preparations of colon tumor cells. Tumor specificity was assessed by immunohistological assays by using frozen sections of normal and malignant human tissues. We now describe a series of studies using two of these antibodies, 16.88 and 28A32, in which further information was obtained concerning the tumor specificity and cellular location of the target antigens reactive with these monoclonal antibodies. Data were acquired from a variety of experimental techniques which included quantitative and qualitative immunofluorescence on live and permeabilized cells, RBC-rosetting assays, immunoperoxidase studies on Cytospin and frozen tissue sections, and immunoblot procedures. These studies show that the 16.88 and 28A32 human monoclonal antibodies bind to antigens which (a) are located in the cell cytoplasm and are not expressed in detectable levels on the cell surface, and (b) are found in many normal and malignant cell types.

Antibodies, Monoclonal↗

PubMed1988

Immunohistochemical characterization of two monoclonal antibodies, P25.48 and P25.91, which define a new prostate-specific antigen.

We have generated two new mouse monoclonal antibodies against prostate cancer. P25.48 (IgG3) and P25.91 (IgG2a) were derived from a fusion using fresh prostate cancer cells as the immunogen. Initial screening was performed by indirect immunofluorescence on frozen tissue sections of prostate cancer specimens. The specificity analysis was performed by indirect immunoperoxidase on frozen sections of normal tissues and benign and malignant prostate tissues. P25.48 and P25.91 did not react with any benign prostatic tissues (0 of 17), but reacted with a subset of the malignant prostatic tissues. Five specimens of well-differentiated carcinoma were tested and did not react with P25.48 or with P25.91. Of 16 higher grade specimens, nine reacted with both P25.48 and P25.91, one reacted with P25.48 only, and one reacted with P25.91 only. In most positive cases, the reactivity was heterogenous. P25.48 and P25.91 showed a very restricted pattern of reactivity in nonprostatic tissues. Of 50 normal specimens, only one breast specimen showed some reactivity. None of the nine fetal tissues or of the 15 malignant tissues tested reacted with these monoclonal antibodies. The pattern of reactivity of P25.48 and P25.91 suggests that they recognize the same antigen. This antigen is selectively expressed by malignant prostatic epithelium. In addition, it appears to be distinct from all other previously described prostate cancer-associated antigens.

Antibodies, Monoclonal↗

PubMed1988

Monoclonal antibodies detect occult breast carcinoma metastases in the bone marrow of patients with early stage disease.

Thirty-five to 40% of patients with operable breast carcinoma develop metastases after primary therapy. There is a need for more specific prognostic parameters to identify patients who are most likely to benefit from adjuvant therapy. The success of such treatment stems from its ability to eradicate preclinical microscopic metastases. The bone marrow is an accessible and frequent site of breast carcinoma metastases. Following studies of Redding et al. (16), we used monoclonal antibodies that recognize membrane and cytoskeletal antigens expressed by epithelial cells (C26, T16, AE-1) in an immunohistochemical assay to find cancer cells in bone marrow aspirates. The assay can detect one cancer cell among 50,000-100,000 hematopoietic cells. None of the 44 control bone marrows (from normal individuals and patients with leukemias and lymphomas) contained antigen-positive (extrinsic) cells. We found extrinsic cells in the bone marrow of 35% (18 of 51) of patients with operable breast carcinoma; no extrinsic cells were identified by routine bone marrow cytology in these patients. Twenty-seven percent (six of 22) of patients with negative lymph nodes had antigen-positive cells, while 41% (12 of 29) of patients with lymph node metastases had such cells. Similarly, 23% (three of 13) of patients with TNM stage I disease, 38% (13 of 34) of patients with stage II disease, and 50% (two of four) of patients with stage III disease had extrinsic cells. In those cases where extrinsic cells were identified, stage II patients with negative lymph nodes and patients with stage I disease were found to have fewer such cells in their marrow than patients with lymph node metastases and patients with stage II disease. These trends did not reach the level of statistical significance in this small number of patients. The presence of extrinsic cells did not correlate with tumor size of lymphatic invasion around the tumor. We conclude that the epithelial cells detected in the bone marrow of the patients with breast carcinoma were carcinoma cells based on the following criteria: (a) they expressed both membrane and cytoplasmic epithelia-specific antigens, (b) they possessed the cytologic characteristics of malignant epithelial cells, and (c) these cells were not detected in the bone marrow from normal individuals or patients with nonepithelial neoplasms involving the bone marrow. We have shown that the technique described here can detect occult metastases in bone marrow and that the presence of extrinsic cells correlates with some established predictors of prognosis. Long-term clinical correlative follow-up studies are now underway.

Antibodies, Monoclonal↗

PubMed1987

Changes in cell surface glycoprotein expression during differentiation of human keratinocytes.

Six cell surface glycoproteins defined by monoclonal antibodies were selected for study on human epidermal cells. In tests on tissue sections, three of the glycoproteins [J143 (gp140/30); T43 (gp85/36); H99 (gp38)] were expressed in the basal cell layer of the epidermis, whereas the other three glycoproteins [T179 (gp140/95); T16 (gp40/50); BT15 (gp80)] were preferentially expressed in maturing keratinocytes above the basal layer. We compared synthesis of these glycoproteins in fresh epidermis and in primary epidermal short term cultures using [35S]methionine for metabolic labeling. Synthesis of J143 was 8- to 20-fold higher and synthesis of T43 was 4- to 10-fold lower in cultured cells compared with fresh epidermis. BT15, an antigen strongly expressed on terminally differentiating keratinocytes, was synthesized at 5- to 15-fold higher levels in fresh epidermis than in cultured cells. Biosynthesis levels of H99, T179, and T16 did not change in cultured epidermal cells. Based on our findings, we propose a model of surface antigenic changes that occur during keratinocyte differentiation in vivo.

Adult↗

PubMed1986

Specificity analysis of human monoclonal antibodies reactive with cell surface and intracellular antigens.

Over 4350 human Ig-secreting hybrids have been generated through the fusion of human lymphocytes with NS-1 (mouse), LICR-2, SKO-007, GM4672, or UC729-6 (human) myeloma and lymphoblastoid cell lines. NS-1 proved to be the most satisfactory fusion partner, and 83% of the stable Ig-secreting clones were derived from NS-1 fusions. Three hundred five hybrids produced human monoclonal antibodies (hmAb) reactive with cell surface or intracellular antigens expressed by cultured human tumor cell lines, and 111 of these have undergone detailed serological specificity analysis. Several general points have emerged from our study of hmAb: A significant proportion of the human B-cell clones produce antibody reactive with cellular antigens. The majority of these antigens have an intracellular location and are broadly distributed. Intracellular and cell surface differentiation antigens and other antigens with restricted distribution have been defined by hmAb, including two cell surface antigens not detected on normal cells. The relationship of these findings to cancer is unclear, as hmAb reactive with antigens showing distinctive distribution have been generated from the lymphocytes of normal individuals as well as tumor-bearing patients.

Antibodies, Monoclonal↗

PubMed1984

Analysis of human monoclonal antibodies derived from lymphocytes of patients with cancer.

Human lymphocytes from tumor-bearing patients and normal individuals have been fused with the NS-1 mouse myeloma line or the LICR -LON- HMY2 ( LICR -2) or SK0 -007 human cell lines. For a given number of lymphocytes, fusions with NS-1 produced 8 times more clones than fusions with LICR -2 and greater than 20 times more clones than fusions with SK0 -007. The percentage of clones that secrete human immunoglobulin (Ig) and the range of Ig production were comparable for clones derived from the three myeloma/lymphoblastoid lines. Clones derived from fusions with LICR -2 and SK0 -007 were found to secrete new species of light and heavy Ig chains in addition to those of the myeloma/lymphoblastoid lines, and clones derived from fusions with NS-1 secreted human Ig and contained both mouse and human chromosomes, which indicates that true hybrid cells were derived from fusions with each of the myeloma/lymphoblastoid lines under study. The stability of Ig production was similar for clones derived from fusions with NS-1, LICR -2, or SK0 -007; these results were comparable to those obtained with standard mouse/mouse hybrids. Stable clones producing human monoclonal antibodies that react with cell surface, cytoplasmic, cytoskeletal, nuclear, or nucleolar antigens have been isolated from tumor-bearing patients and normal individuals. A number of human monoclonal antibodies reactive with cytoskeletal antigens appear to be directed against components of the intermediate filament family. Techniques for the production of human monoclonal antibody appear to be sufficiently advanced to initiate a serological dissection of the humoral immune response to cancer.

Animals↗

PubMed1983

Detection of cell surface and intracellular antigens by human monoclonal antibodies. Hybrid cell lines derived from lymphocytes of patients with malignant melanoma.

This study represents an initial attempt to analyze the humoral immune reactions of patients with malignant melanoma by hybridoma methodology. Using lymphocytes from regional lymph nodes, peripheral blood and tumor infiltrates, 158 fusions were performed with SKO-007 (human myeloma line), LICR-LON-HMy2 (LICR-2), GM 4672 (human lymphoblastoid lines), or NS-1 (mouse myeloma line). Fusion of lymph node lymphocytes with NS-1 resulted in a 3-4 times higher frequency of clones than fusion with LICR-2, and a 10 times higher frequency than fusion with SKO-007 or GM 4672. In the case of peripheral blood lymphocytes, fusion with NS-1 gave greater than 25 times higher frequency of clones than fusion with LICR-2 or SKO-007. Production of human mu, gamma, or alpha heavy chains was detected in 50-80% of wells containing growing clones, and the levels of immunoglobulin ranged from 0.3 micrograms to 40 micrograms/ml. NS-1-derived clones could be easily subcultured, while LICR-2 and SKO-007 clones grew more slowly on subculturing. In this study, Ig secretion appeared to be a more stable property of LICR-2-derived clones than NS-1-derived clones. A panel of 20 human cancer cell lines was used to screen 771 Ig-secreting cultures for antibody to cell surface or intracellular antigens. Reactivity with cell surface antigens was found infrequently (6 cultures), whereas reactivity with intracellular antigens was more common (27 cultures). A new cell surface antigen with properties of a glycolipid was defined with an IgM monoclonal antibody secreted by a tetraploid cell derived from a fusion of LICR-2 with lymphocytes from the axillary lymph node of a patient with melanoma. The hybrid cell line has been subcloned four times and secretes 5 micrograms IgM/ml. The antigen detected by this IgM antibody was found on 5 of 23 melanoma cell lines and 12 of 30 epithelial cancer cell lines. No reactions were found with 11 cultures derived from normal cells. Stable cell lines secreting human antibody that detected nuclei, nucleoli, cytoskeletal elements, Golgi complex, or other cytoplasmic components were also isolated in this study. One of these antibodies detected an intracellular antigen that is restricted to cells of neuroectodermal derivation, and a second antibody reacted primarily with cells of epithelial origin. Using these methods to isolate and analyze human monoclonal antibody, it should now be possible to define the repertoire of the humoral immune response to melanoma.

Animals↗