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S von Mensdorff-Pouilly

Publications and source records attributed to S von Mensdorff-Pouilly.

At least 19 recordsLinked to original sources
PubMed2001

Antibody-dependent cell-mediated cytotoxicity can be induced by MUC1 peptide vaccination of breast cancer patients.

Human polymorphic epithelial mucin (PEM, MUC1) is a high molecular weight transmembrane glycoprotein expressed on the apical cell surface of glandular epithelium and is over-expressed and hypo-glycosylated in adenocarcinomas. The extracellular part of the molecule consists mainly of a variable number of 20 amino acid repeats that contain cryptic epitopes exposed in malignancy. The objective of our study was to determine whether humanized MUC1 MAbs and Abs induced by vaccination of breast cancer patients with MUC1 peptides can effect an antibody-dependent cell-mediated cytotoxicity (ADCC). An in vitro assay has been set up in which the breast tumor cell line ZR-75-1 is used as target and PBMC of healthy donors as effector cells. Different target and effector cells, as well as various MUC1 MAbs were tested to optimize the efficacy of the in vitro assay. The humanized MAb HuHMFG-1, which recognizes the PDTR sequence in the MUC1 tandem repeat, induced a strong cell-mediated cytotoxicity. Nine MUC1-expressing tumor cell lines, including 3 bone marrow-derived cell lines, as well as 2 MUC1-transfected cell lines were susceptible to different extent to MUC1 Ab-dependent killing. Large variations in the killing capacity of PBMC from healthy donors were found. The NK cells were the essential effector cells for the MUC1 Ab-dependent killing. Plasma samples with induced high levels of MUC1 Ab were obtained from breast cancer patients repeatedly immunized with a KLH-conjugated 33-mer or 106-mer MUC1 tandem repeat. Pre- and post-vaccinated plasma samples of these patients were compared in the ADCC assay and it could be clearly demonstrated that the induced MUC1 Abs can effect tumor cell killing. MUC1 Ab-dependent cell-mediated tumor cell killing may occur in vivo and the ADCC assay can be applied to monitor MUC1 vaccination trials.

Amino Acid Sequence↗
PubMed2001

T cell infiltration and MHC I and II expression in the presence of tumor antigens: An immunohistochemical study in patients with serous epithelial ovarian cancer.

OBJECTIVES: Ovarian cancer is a frequent cause of death among women with gynaecologic malignancies despite the introduction of combination chemotherapy. There is therefore a need for new therapeutic strategies for patients with ovarian cancer, such as cellular immunotherapy. In this immunohistochemical study we analysed the expression of three tumor antigens, p53, HER-2/neu and MUC-1 in relation to the expression of major histocompatibility complex (MHC) class I and II on tumor cells, and we searched for the presence of (activated) immune effector cells at the tumor site. STUDY DESIGN: The study was carried out retrospectively in tumor tissue from 29 patients with serous ovarian cancer. Material used had been formalin fixed and paraffin embedded. Material had been obtained from 15 patients at staging laparotomy and from 14 patients during second look or intervention laparotomy. RESULTS: A positive staining for p53 was found in 19/29 (66%) of the tumors, with a high positivity in 13/29 (45%). HER-2/neu and MUC-1 staining was positive in 8/29 (28%) and 21/28 (75%), respectively. Downregulation of MHC class I on tumor cells was found in a minority of the patients, beta-2-microglobin (beta2m) was expressed on tumor cells in all patients. High staining for CD45RO correlated with a high positive staining for granzyme-B (R=0.40, P=0.04) and TIA-1 (R=0.39, P=0.04). A statistically significant better survival in the group with lower stage of disease was found. CONCLUSIONS: As only three out of 29 patients were negative for the tumor antigens p53, HER-2/neu and MUC-1, immunotherapy aiming at all three could serve almost all patients with ovarian cancer. We found that granzyme-B, TIA-1 and CD45RO+ T cells are present in the tumor biopsies, increasing this number by immunotherapy may be beneficial. The immune escape mechanism by MHC class I and beta2m downregulation seems to be of minor importance. Our data support the view that immunotherapy may offer new possibilities with high specificity in ovarian cancer.

Adult↗
PubMed2001

MUC1 (EMA) is preferentially expressed by ALK positive anaplastic large cell lymphoma, in the normally glycosylated or only partly hypoglycosylated form.

AIMS: To investigate whether MUC1 mucin, a high molecular weight transmembrane glycoprotein, also known as epithelial membrane antigen (EMA), differs in its expression and degree of glycosylation between anaplastic large cell lymphoma (ALCL) and classic Hodgkin's disease (HD), and whether MUC1 immunostaining can be used to differentiate between CD30 positive large cell lymphomas. METHODS/RESULTS: Using five different monoclonal antibodies (E29/anti-EMA, DF3, 139H2, VU-4H5, and SM3) that distinguish between various MUC1 glycoforms, high MUC1 expression (50-95% of tumour cells positive) was found in 13 of 17 anaplastic lymphoma kinase (ALK) positive systemic nodal ALCLs, and in one of 20 cases of classic HD. Scattered or focal staining (< 25% of tumour cells) was seen in two additional ALK positive systemic ALCLs, two additional classic HD cases, and in three of 20 cases of ALK negative systemic nodal ALCL. Primary cutaneous ALCL showed no staining with the anti-MUC1 antibodies. Antibodies detecting hypoglycosylated MUC1 were found to be absent in all lymphomas (SM3) or present in only six of 15 ALK positive ALCLs (VU-4H5). CONCLUSIONS: MUC1 is preferentially expressed by a subtype of systemic nodal ALCL, characterised by ALK expression, but is found in only a few cases of classic HD and ALK negative ALCL. Therefore, although MUC1 could be used in a panel of markers for CD30 positive lymphomas, it is probably not a valuable tool to differentiate between ALK negative CD30 positive large cell lymphomas. Finally, the degree of MUC1 glycosylation in lymphomas is relatively high, compared with the aberrant hypoglycosylation found in adenocarcinomas.

Anaplastic Lymphoma Kinase↗
PubMed2000

Elevated soluble MUC1 levels and decreased anti-MUC1 antibody levels in patients with multiple myeloma.

Soluble MUC1 (sMUC1) levels are elevated in many MUC1(+) cancers. We and others have shown that MUC1 is expressed on multiple myeloma (MM) plasma cells and B cells. In this study, we measured sMUC1 levels in bone marrow (BM) plasma from 71 MM patients and 21 healthy donors (HDs), and in peripheral blood (PB) plasma from 42 MM patients and 13 HDs using an immunoassay that detects the CA27.29 epitope of MUC1. sMUC1 levels were found to be significantly greater (mean 31.76 U/mL, range 5.69 to 142.48 U/mL) in MM patient BM plasma versus HD BM plasma (mean 9.68 U/mL, range 0.65 to 39.83 U/mL) (P <. 001). Importantly, BM plasma sMUC1 levels were related to tumor burden because sMUC1 levels were significantly higher for MM patients with active disease (34.62 U/mL, range 5.69 to 142.48 U/mL) versus MM patients with minimal residual disease (16.16 U/mL, range 5.7 to 56.68 U/mL) (P =.0026). sMUC1 levels were also elevated in the PB plasma of MM patients (32.79 U/mL, range 4.15 to 148.84 U/mL) versus HDs (18.47 U/mL, range 8.84 to 42.49) (P =.0052). Lastly, circulating immunglobulin M (IgM) and IgG antibodies to MUC1 were measured in 114 MM patients and 31 HDs, because natural antibodies to MUC1 have been detected in patients with other MUC1-bearing malignancies. These studies demonstrated lower levels of circulating IgM (P <.001) and IgG (P =.078) antibodies to MUC1 in MM patients compared with HDs. Our data therefore show that in MM patients, sMUC1 levels are elevated and correlate with disease burden, whereas anti-MUC1 antibody levels are decreased.

Autoantibodies↗
PubMed2000

Reactivity of natural and induced human antibodies to MUC1 mucin with MUC1 peptides and n-acetylgalactosamine (GalNAc) peptides.

Antibodies (Abs) to MUC1 occur naturally in both healthy subjects and cancer patients and can be induced by MUC1 peptide vaccination. We compared the specificity of natural and induced MUC1 Abs with the objective of defining an effective MUC1 vaccine for active immunotherapy of adenocarcinoma patients. Serum samples, selected out of a screened population of 492 subjects for their high levels of IgG and/or IgM MUC1 Abs, were obtained from 55 control subjects and from 26 breast cancer patients before primary treatment, as well as from 19 breast cancer patients immunized with MUC1 peptides coupled to keyhole limpet hemocyanin (KLH) and mixed with QS-21. The samples were tested with enzyme-linked immunoassays for reactivity with (1) overlapping hepta- and 20-mer peptides spanning the MUC1 tandem repeat sequence; (2) two modified 60-mer peptides with substitutions in the PDTR (PDTA) or in the STAPPA (STAAAA) sequence of each tandem repeat; and (3) four 60-mer glycopeptides with each 1, 2, 3 and 5 mol N-acetylgalactosamine (GalNAc) per repeat. More than one minimal epitopic sequence could be defined, indicating that Abs directed to more than one region of the MUC1 peptide core can coexist in one and the same subject. The most frequent minimal epitopic sequence of natural MUC1 IgG and IgM Abs was RPAPGS, followed by PPAHGVT and PDTRP. MUC1 peptide vaccination induced high titers of IgM and IgG Abs predominantly directed, respectively, to the PDTRPAP and the STAPPAHGV sequences of the tandem repeat. Natural MUC1 Abs from breast cancer patients reacted more strongly with the N-acetylgalactosamine (GalNAc) peptides than with the naked 60-mer peptide, while reactivity with the GalNAc-peptides was significantly reduced (2-tailed p < 0.0001) in the MUC1 IgG and IgM Abs induced by MUC1 peptide vaccination. Whereas in cancer patients glycans appear to participate in epitope conformation, the epitope(s) recognized by MUC1 Abs induced by peptide vaccination are already masked by minimal glycosylation. Therefore, our results indicate that a MUC1 glycopeptide would be a better vaccine than a naked peptide.

Acetylgalactosamine↗
PubMed2000

Survival in early breast cancer patients is favorably influenced by a natural humoral immune response to polymorphic epithelial mucin.

PURPOSE: Polymorphic epithelial mucin (PEM or MUC1) is being studied as a vaccine substrate for the immunotherapy of patients with adenocarcinoma. The present study analyzes the incidence of naturally occurring MUC1 antibodies in early breast cancer patients and relates the presence of these antibodies in pretreatment serum to outcome of disease. MATERIALS AND METHODS: We measured immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to MUC1 with an enzyme-linked immunoassay (PEM.CIg), which uses a MUC1 triple-tandem repeat peptide conjugated to bovine serum albumin, in pretreatment serum samples obtained from 154 breast cancer patients (52 with stage I disease and 102 with stage II) and 302 controls. The median disease-specific survival time of breast cancer patients was 74 months (range, 15 to 118 months). A positive test result was defined as MUC1 IgG or IgM antibody levels equal to or greater than the corresponding rounded-up median results obtained in the total breast cancer population. RESULTS: A positive test result for both MUC1 IgG and IgM antibodies in pretreatment serum was associated with a significant benefit in disease-specific survival in stage I and II (P =.0116) breast cancer patients. Positive IgG and IgM MUC1 antibody levels had significant additional prognostic value to stage (P =.0437) in multivariate analysis. Disease-free survival probability did not differ significantly. However, stage II patients who tested positive for MUC1 IgG and IgM antibody and who relapsed had predominantly local recurrences or contralateral disease, as opposed to recurrences at distant sites in the patients with a negative humoral response (P =.026). CONCLUSION: Early breast cancer patients with a natural humoral response to MUC1 have a higher probability of freedom from distant failure and a better disease-specific survival. MUC1 antibodies may control hematogenic tumor dissemination and outgrowth by aiding the destruction of circulating or seeded MUC1-expressing tumor cells. Vaccination of breast cancer patients with MUC1-derived (glyco)peptides in an adjuvant setting may favorably influence the outcome of disease.

Adolescent↗
PubMed1999

Aberrant expression of MUC1 mucin in ductal hyperplasia and ductal carcinoma In situ of the breast.

MUC1 mucin is a high molecular weight transmembrane glycoprotein expressed on the apical cell surface of normal glandular epithelia. In many human adenocarcinomas, this protein is up-regulated and/or underglycosylated, and its expression changes from apical to the entire cell membrane. It is thought that entire cell membrane expression of MUC1 reduces cell-cell and cell-extracellular matrix interactions and therefore may facilitate invasive growth and development of metastases. In this study, we determined immunohistochemically the expression of normal and underglycosylated MUC1 in normal breast tissue (n = 8) and in a spectrum of breast lesions, including usual ductal hyperplasia (n = 23), atypical ductal hyperplasia (n = 7), and ductal carcinoma in situ (DCIS) (n = 22). We used 4 monoclonal antibodies; 115D8 is directed to a glycopeptide, the other 3 to the peptide core of the molecule, of which 139H2 is not affected by the degree of glycosylation of MUC1, whereas SM3 and VU-4-H5 stain only underglycosylated forms. All cases showed apical positivity for 115D8 and 139H2. Entire cell membrane expression of fully (normal) glycosylated MUC1 was mainly found in DCIS lesions. Apical staining of SM3 was found in 38% of normal cases and 60% of the ductal lesions with no difference between the different subgroups. Apical staining of VU-4-H5 was found more often in DCIS (27%) than in normal tissue or ductal hyperplasia (3%). Membrane expression of underglycosylated MUC1 was found only in poorly differentiated DCIS. In conclusion, aberrant expression of MUC1, i.e., on the entire cell membrane and/or underglycosylated forms, can be found in ductal hyperplasia with atypia and especially in DCIS of the breast. This finding implies that these lesions with aberrant expression are at higher risk for developing subsequent invasive breast carcinoma.

Antibodies, Monoclonal↗
PubMed1999

CA 125: fundamental and clinical aspects.

Since the OC 125 monoclonal antibody (Mab) was generated, other Mabs to the CA 125 glycoprotein have been produced and classified into two families associated with two major epitope regions on the CA 125 molecule. New generation assays, combining Mabs to two distinct regions of the molecule, compare favorably with that of the original assays as demonstrated by ROC curves. The original CA 125 assay suffered from interference of HAMA, an important drawback considering the increasing use of murine antibodies for immunodiagnosis and treatment of ovarian cancer. This problem has been solved for the majority of currently available tests. The sensitivity of the assays for early ovarian cancer remains low, precluding its indiscriminate use for screening and diagnosis of ovarian cancer. Its use in screening for early cancer, combined with ultrasonography, is limited to high risk populations, such as women from families with mutations in the BRCA1 or 2 gene. Although CA 125 assessment may play a limited role in the (early) detection of ovarian cancer, its role in the follow-up during and after therapy is well established. The major contribution of CA 125 is in the monitoring of tumor response to chemotherapy, where it is valuable in detecting those patients with an inadequate response to the chosen treatment. The role of CA 125 in early detection of recurrences remains to be established and is currently the subject of two large clinical trials.

Animals↗
PubMed1999

Isolation of MUC1-primed B lymphocytes from tumour-draining lymph nodes by immunomagnetic beads.

The humoral immune response against a tumour-associated antigen, polymorphic epithelial mucin (PEM, MUC1) in cancer patients was studied by isolating specific B cells primed for the antigen. Human B lymphocytes from tumour-draining lymph nodes, obtained from 12 patients with epithelial cancers, were immunoselected with magnetic beads coated with a 60mer synthetic peptide corresponding to three tandem repeats of the protein core of the MUC1 antigen. Short-term cultures of B cells were established utilizing interleukin-10 (IL-10), IL-4 and monoclonal antibody anti-CD40, and were maintained for a maximum of 3 weeks. B cell culture supernatants contained human anti-MUC1 antibodies, as detected by enzyme-linked immunosorbent assay, in 6/12 of the patients tested. Five of these patients, all with early-stage cancer, also had high levels of circulating anti-MUC1 IgM antibodies in the serum. A significant correlation was found (two-tailed P = 0.041) between the presence of circulating anti-MUC1 antibodies and the ability to isolate PEM-specific B cells from tumour-draining lymph nodes. The technique proposed provides a useful method for the analysis of natural immunity against defined tumour antigens.

Adult↗
PubMed1999

Cellular and humoral immune responses to MUC1 mucin and tandem-repeat peptides in ovarian cancer patients and controls.

The objective of this study was to demonstrate the presence of proliferative T cell responses to human polymorphic epithelial mucin (MUC1) and its tandem-repeat peptides in peripheral blood mononuclear cells (PBMC) from ovarian cancer patients and from controls and to correlate these cellular responses to a humoral response to MUC1. PBMC were obtained from 6 healthy women, from 13 women in the third trimester of pregnancy and from 21 ovarian cancer patients. Only 1 of the 6 healthy women showed a weak primary proliferative response (stimulation index, SI <2) to a 20-mer MUC1 tandem-repeat peptide in the presence of interleukin-2 (IL-2). In PBMC from 5/13 pregnant women (38%) a weak response could be induced by the 20-mer and/or 60-mer tandem-repeat peptides (SI < or =3.0) and in PBMC from 8/15 ovarian cancer patients (53%) 20-mer and/or 60-mer MUC1 tandem-repeat peptides induced primary responses (SI < or =5.4). MUC1 mucin purified from a breast tumor cell line and/or from urine of a healthy donor had a relatively strong stimulating effect (SI < or =19) on PBMC from 4 of 16 ovarian cancer patients (25%). In contrast, in PBMC of 9 ovarian cancer patients stimulated by the addition of a Candida albicans extract, MUC1 mucin strongly inhibited proliferation. This inhibition could partially be abrogated by the addition of IL-2. MUC1 (CA 15.3 assay) and free circulating MUC1 IgG and IgM antibodies (PEM.CIg assay) were determined in the plasma of all subjects. The MUC1 and the free circulating MUC1 IgG antibody plasma levels were significantly higher in the ovarian cancer patients than in the healthy women. Although no significant correlations were found between MUC1 mucin, MUC1 Ab plasma levels and the individual proliferative responses to the MUC1 antigens, an association may exist between them, since all three are significantly higher in the ovarian cancer patients than in the healthy women.

Amino Acid Sequence↗
PubMed1999

Quantification of MUC1 in breast cancer patients. A method comparison study.

OBJECTIVE: To compare the performance of four serum assays for the quantification of MUC1 in breast cancer patients. STUDY DESIGN: A total of 282 serum samples were evaluated with two automated (Boehringer Mannheim Enzymun-Test CA 15-3 and Chiron ACS BR) and two manual assays (Centocor CA 15-3 radioimmunoassay [RIA] and Biomira Truquant BR RIA). Sera were obtained from healthy controls (n=50), patients with benign (n=25) and malignant breast disease (n=77) and patients with other malignancies (n=69). In addition, sera from pregnant women (n=56) and patients with liver cirrhosis (n=5) were included. RESULTS: Intraassay coefficients of variation (C.V.s) were highest for the manual Centocor CA 15-3 assay (7.4% for values below 50 kU/l and 8.1% for values above 180 kU/l). Interassay C.Vs were highest for the manual Truquant BR assay (11.7% for the lower concentration values and 18.6% for the higher concentration values). False positive rates ranged between 0% for the Centocor CA 15-3 RIA and 14% for the ACS BR assay (cut-off: 30 kU/l). In monitoring breast cancer patients all four assays show similar patterns, although absolute MUC1 values found may differ up to 50%. CONCLUSION: For monitoring purposes all assays perform equally well, however, automated assays show lower inter- and intraassay variability, especially in the higher value range. Therefore we recommend the use of the same, automated, assay for quantification of MUC1 during the follow-up of breast cancer patients.

Biomarkers, Tumor↗
PubMed1998

Human single-chain Fv antibodies to MUC1 core peptide selected from phage display libraries recognize unique epitopes and predominantly bind adenocarcinoma.

The tumor-associated antigen MUC1 is overexpressed and underglycosylated in human adenocarcinomas of diverse origins, such as breast, ovary, and colon. We isolated and describe five human single-chain (sc) Fv antibodies specific for the MUC1 variable number of tandem repeats region isolated by in vitro selection from a large naive phage antibody library containing over 6 x 10(9) different scFv antibodies. A synthetic biotinylated 100-mer peptide corresponding to five tandem repeats of the MUC1 peptide core was used for selection. Two of the antibodies were highly specific for MUC1 as judged by ELISA and flow cytometry. In immunohistochemistry, antibody clone 10A stained MUC1 in the cytoplasm and membrane of adenocarcinoma cells of breast and ovary, whereas in normal epithelium, only cytoplasmic or no staining was observed. With antibody clone 10B, staining was less pronounced and was not always membrane associated in adenocarcinoma. Determination of the fine specificity of 10A and 10B using a novel "indirect epitope fingerprinting" ELISA showed that both antibodies recognize unique epitopes that have not been described for hybridoma-derived anti-mucin antibodies of mouse origin. The selected human antibodies, like many of the murine MUC1 antibodies, recognize epitopes on the protein core of MUC1 that are abundantly present in the underglycosylated form of cell surface mucin on adenocarcinoma. The best human scFv, clone 10A, appears to distinguish normal cells from adenocarcinoma cells, which makes it an attractive candidate for use in antibody-based tumor targeting.

Adenocarcinoma↗
PubMed1998

An enzyme-linked immunosorbent assay for the measurement of circulating antibodies to polymorphic epithelial mucin (MUC1).

INTRODUCTION: About one-third of breast and ovarian carcinoma patients have circulating antibodies reactive with polymorphic epithelial mucin (MUC1), either free or bound to immune complexes. While the presence of these immune complexes has prognostic significance in breast cancer patients, the significance of free MUC1 antibodies is less clear. The objective of this study was to develop a reliable assay for the accurate determination of circulating free antibodies to MUC1. MATERIAL AND METHODS: We developed an enzyme-linked immunosorbent assay (ELISA) (PEM.CIg) employing a 60 mer peptide (a triple tandem repeat sequence of the MUC1 peptide core) conjugated to bovine serum albumin and peroxidase-labeled antihuman immunoglobulin G or M antibodies. The assay was standardized and its analytical performance evaluated. A total of 492 serum samples were obtained from 40 healthy men, from 201 healthy women (including 55 women without a history of pregnancy and 45 pregnant women), and (before primary treatment) from 62 benign breast tumor patients and 190 breast cancer patients. MUC1 serum levels were determined with commercial CA 15-3 tests. RESULTS: Circulating antibodies to MUC1 are present both in healthy subjects and in breast cancer patients. The within- and between-assay coefficients of variation were, respectively, 2 and 12% for the IgG determinations and 1.2 and 3% for the IgM determinations. Correlation coefficients for serially diluted serum samples ranged from 0.9998 to 0.9920 for IgG and from 0.9996 to 0.9818 for IgM determinations. The reactivity of serum samples was partially blocked by the addition of various MUC1 peptides and by MUC1 mucin. The inhibiting effect of modified 60 mer peptides suggests the presence of antibodies directed to more than one epitope. CONCLUSIONS: The PEM. CIg assay is a reliable ELISA for measuring free MUC1 antibodies in serum. We are in the process of relating the results obtained in the breast cancer group to disease outcome to evaluate its prognostic significance. In addition, the assay may become a useful tool for vaccine therapy monitoring.

Autoantibodies↗
PubMed1998

Summary report on the ISOBM TD-4 Workshop: analysis of 56 monoclonal antibodies against the MUC1 mucin. San Diego, Calif., November 17-23, 1996.

Sixteen research groups participated in the ISOBM TD-4 Workshop in which the reactivity and specificity of 56 monoclonal antibodies against the MUC1 mucin was investigated using a diverse panel of target antigens and MUC1 mucin-related synthetic peptides and glycopeptides. The majority of antibodies (34/56) defined epitopes located within the 20-amino acid tandem repeat sequence of the MUC1 mucin protein core. Of the remaining 22 antibodies, there was evidence for the involvement of carbohydrate residues in the epitopes for 16 antibodies. There was no obvious relationship between the type of immunogen and the specificity of each antibody. Synthetic peptides and glycopeptides were analyzed for their reactivity with each antibody either by assay of direct binding (e.g. by ELISA or BiaCore) or by determining the capacity of synthetic ligands to inhibit antibody binding interactions. There was good concordance between the research groups in identifying antibodies reactive with peptide epitopes within the MUC1 protein core. Epitope mapping tests were performed using the Pepscan analysis for antibody reactivity against overlapping synthetic peptides, and results were largely consistent between research groups. The dominant feature of epitopes within the MUC1 protein core was the presence, in full or part, of the hydrophilic sequence of PDTRAPAP. Carbohydrate epitopes were less easily characterized and the most useful reagents in this respect were defined oligosaccharides, rather than purified mucin preparations enriched in particular carbohydrate moieties. It was evident that carbohydrate residues were involved in many epitopes, by regulating epitope accessibility or masking determinants, or by stabilizing preferred conformations of peptide epitopes within the MUC1 protein core. Overall, the studies, highlight concordance between groups rather than exposing inconsistencies which gives added confidence to the results of analyses of the specificity of antimucin monoclonal antibodies.

Amino Acid Sequence↗
PubMed1998

'Epitope fingerprinting' using overlapping 20-mer peptides of the MUC1 tandem repeat sequence.

The ISOBM TD-4 Workshop antibodies 122-177 were tested for reactivity with 20 overlapping MUC1 tandem repeat 20-mer peptides by an ELISA, in order to determine the complete amino acid sequences of the epitopes. Of the 56 antibodies studied, 30 showed specific binding and thus the epitopes were characterized. The epitopes appear to be 'broader' when compared to those deduced from studies using smaller peptides. Interassay variation is remarkably small, allowing for precise grouping of clusters with very similar epitope patterns. Five groups of antibodies show remarkable similarity: BC3 and VU-4-H5; BC4W154, C595 and Mc5; MF06 and B27.29; VU-11-D1 and VU-11-E2; Ma552, VU-3-C6, 7540MR and BC4E549. We have used the term 'epitope fingerprinting' to refer to the 'fine structure' of the epitope with all its essential and flanking amino acids. We believe this method is more precise than the usual epitope mapping with short peptides.

Amino Acid Sequence↗
PubMed1997

Autoantibodies to p53 in ovarian cancer patients and healthy women: a comparison between whole p53 protein and 18-mer peptides for screening purposes.

Autoantibodies against complete p53 protein and 18-mer peptides of p53 in ovarian cancer patients and healthy women were examined. Sera from 9% (4/46) of ovarian cancer patients but none (0/51) of healthy women recognized complete p53 protein. The antibodies were mainly of the IgG1 isotype. Two patients had also IgG2 antibodies. Sera from 28% (13/46) of cancer patients and 21% (11/52) of healthy women contained either IgM, or IgM plus IgG2 antibodies against 18-mer p53 peptides. Screening against complete p53 protein instead of peptides seems necessary for identifying patients with tumor-related antibodies. IgG2 antibodies against p53 suggest p53-specific CD4+ T helper 1 cell activity in some of the ovarian cancer patients.

Autoantibodies↗
PubMed1997

Clinical and technical evaluation of ACS BR serum assay of MUC1 gene-derived glycoprotein in breast cancer, and comparison with CA 15-3 assays.

The mucin glycoprotein-detecting assay CA 15-3 is a valuable tool for monitoring the course of disease in breast cancer patients. Assays of CA 15-3 are based on the use of two MAbs to polymorphic epithelial mucin (PEM). We evaluated the technical and clinical performance of the Chiron ACS BR, an automated competitive chemiluminescence assay using a single MAb, B27.29, and compared the assay's results with those of the Centocor CA 15-3 RIA, the Abbott IMx CA 15-3, and the Boehringer Mannheim Enzymun-Test CA 15-3. The study population consisted of 253 healthy women, 66 patients with benign breast disease, 168 breast cancer patients, and 76 patients with other carcinomas. In the technical evaluation, we assessed the precision and linearity on dilution of the ACS BR assay. Cutoff values (upper limits of values seen in healthy subjects) were determined for all four assays. Agreement between the assays was studied by linear regression analysis. The ACS BR assay gave within- and between-assay CVs of 2.2% and 3.9%, respectively. Three samples from healthy women gave discordant values by ACS BR and were not included in the calculations. All four assays exhibit a highly similar pattern when monitoring breast cancer disease; the closest agreement of values was obtained between ACS BR and Centocor CA 15-3. We conclude that the ACS BR assay is a fast and reliable immunoassay for measuring PEM in serum. Although it detects a slightly different epitope on the PEM molecule than is targeted in other assays, for cancer serum samples it agreed better with the original Centocor CA 15-3 assay than did the other two CA 15-3 assays tested.

Adolescent↗