Jo Hilgers

The Utility of Lipid-Associated Sialic Acid (LASA or LSA) as a Serum Marker for Malignancy

The utility of the lipid-associated sialic acid (LASA or LSA) test as a serum marker for malignancy is reviewed. The name LASA or LSA test is confusing because it suggests that only or mainly lipid-bound sialic acid is measured. In reality, glycoprotein-bound sialic acid is determined predominantly. The assay appears to have a particularly high positivity rate in leukemia, Hodgkins disease, melanoma, sarcoma, advanced ovarian carcinoma and oropharyngeal tumors, suggesting that LASA may serve as a valuable marker in these malignancies. As a consequence of the rise of sialic acid-rich acute-phase proteins, such as alpha 1-acid glycoprotein, in inflammatory diseases the specificity of LASA and therefore its diagnostic accuracy is low. LASA can be useful for monitoring cancer patients during treatment, especially in combination with other tumor markers.

‘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.

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.

Immunohistochemical Characterization of a Panel of 56 Antibodies with Normal Human Small Intestine, Colon, and Breast Tissues

The epithelial mucin MUC1 is heavily but differently glycosylated depending on the origin and developmental status of the tissue, which greatly influences the reactivity of monoclonal antibodies (MAbs). A partial characterization of their epitopes is possible by mild, carbohydrate-specific periodate oxidation of tissue sections prior to immunostaining. Using this strategy, we have evaluated 56 MAbs submitted to the ISOBM TD-4 (MUC1) Workshop. Paraffin sections from normal human small intestine, colon and breast were immunostained at different defined antibody concentrations either directly or after oxidation with 20 mM periodate at pH 5 for 30 min (PO). In addition, monolayers of T-47D breast cancer cells without PO treatment were examined in immunofluorescence. The array of observed reactivities allowed us to classify the MAbs as follows. Fourteen antibodies were found to detect MUC1 largely independent of the degree of glycosylation, and are therefore classified as pan-MUC1 MAbs (Group A). Twenty-four MAbs were nonreactive with one or more types of the examined epithelia, but became reactive after PO of the tissue sections. We have called these differentiation-dependent MUC1 MAbs (Group B). They might be especially valuable in histological tumour diagnosis. According to their differential staining behaviour towards untreated small intestine, colon, and breast tissue sections, we divided these MAbs into 4 subtypes (Group B1 through Group B4). A further group of six MAbs detected PO-sensitive carbohydrate epitopes (Group C). A seventh antibody apparently also belongs to Group C by immunohistological criteria, although its corresponding epitope was not PO-sensitive. Three further MAbs are still unclear in their specificity, and another 2 are not MUC1-specific (Group D). Six preparations were found nonreactive with the examined tissues; 4 of these were also negative with T-47D cells. Generally, a broad spectrum of different immunohistological patterns has emerged which appears to be widely independent of the type of epitope (sequence versus conformational, length of sequence) and the relative affinities determined in vitro.

Influence of chemotherapy on the expression of p53, HER-2/neu and proliferation markers in ovarian cancer

OBJECTIVEnMutated p53 and HER-2/neu play a role in the etiology of ovarian cancer. It is important to know whether the expression of these proteins is affected by platinum-containing chemotherapy.nnnSTUDY DESIGNnTogether with the cell proliferation markers Ki-67 and PCNA, the expression of p53 and HER-2/neu was assessed before and after chemotherapy. Paraffin-embedded tumor sections from 20 patients with ovarian cancer and four patients with benign disorders of the ovaries (controls) were analyzed. The expression of p53 was determined by the antibodies DO-1 and BP53-12. In addition to HER-2/neu and PCNA specific antibodies, MIB-1 was used to detect Ki-67.nnnRESULTSnThe expression of all markers was higher in ovarian cancer patients than in non-malignant controls. MIB-1 showed a significant increase of expression after chemotherapy (P=0.002). HER-2/neu, p53 and PCNA also showed a clear increase after treatment, but this was not statistically significant. HER-2/neu is of prognostic relevance with respect to the response to chemotherapy (P=0.005) and survival (P=0.0002).nnnCONCLUSIONnThe different markers tested all increase after chemotherapy, but the differences are not statistically significant. Low HER-2/neu expression correlates with good outcome at second look.

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

OBJECTIVEnTo compare the performance of four serum assays for the quantification of MUC1 in breast cancer patients.nnnSTUDY DESIGNnA 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.nnnRESULTSnIntraassay 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%.nnnCONCLUSIONnFor 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.

Monoclonal antibodies against CA125-bearing antigenic molecule fragments; reactivity with mucinous ovarian tumours and lung cancers

We first established a cell strain, SHIN-3, from human ovarian serous cystadenocarcinoma, and performed antigen analysis for CA125 which appeared to be massively secreted by the SHIN-3 cells. Protein digestion analysis revealed that a low molecular weight peptide of 49 kDa showed antigen activity. In the present study, we describe a mouse monoclonal antibody against this low molecular peptide, presumed to be part of the CA125-bearing antigenic molecule. Purified antigen prepared from culture supernatant was adsorbed to nitrocellulose membranes and injected intrasplenically in mice. Of the obtained 398 clones, 10 clones were selected by screening in an ELISA test. Of the 10, two were further selected, i.e. SH-9. This hybridoma produces IgG1 monoclonal antibodies. Immunoblotting analysis revealed that SH-9 recognizes the low molecular peptide used as the immunogen. Immunohistological examination with the SH-9 MAb revealed that the antigen reacted with the bronchial epithelium, cervical glands of the uterus and other various normal tissues. Of tumorous tissues, the antibody mainly reacted with ovarian tumours, but positive reactions were also observed with pulmonary adenocarcinomas or squamous cell carcinomas. Surprisingly the positive rate was high in mucinous tumour of the ovary, while no positive reaction was observed in serous tumours. Dot-blot assay using SH-9 revealed that 17/19 (90%) sera of lung cancer patients were positive for the titre suggesting that SH-9 may be useful to set up a serum test for lung cancers.

A new hereditary cataract mouse with lens rupture

A new cataract model originated in a recombinant inbred (RI) strain, CXS4 or CXSD (D), between BALB/cHeA(BALB/c or C) and STS/A(STS or S) mice. Opacity appeared as a white pinpoint focus in unpigmented eyes of albino mice from 5 weeks old. All the mice were bilaterally affected by 14 weeks old. They were fully viable and fertile. There was no sex difference in incidence of cataract. Histologically, the 3-4 months old mice showed vacuoles in the lens cortex. The vacuoles were spread all over the lens cortex in advanced cases. Ruptures of the lens nucleus to the vitreous chamber was a typical occurrence. For elucidation of the mode of inheritance, F1 hybrids (CXD and SXD) and backcross progenies [(CXD)F1XD and (SXD)F1XD] were analysed. No affected mice were observed in F1 hybrids. In backcross progenies, the segregation ratio of affected and normal mice was close to 1:1 in both matings. We conclude that the cataract is inherited by an autosomal single recessive gene. This mutant gene is provisionally named lens rupture 2 (gene symbol lr2, Mouse Genome Database Accession No. MGD-JNUM-37399). The new cataract model mouse will be a good tool for the genetic analysis and molecular biological study of cataractogenesis.

Immunohistochemical expression of MAM-3 and MAM-6 antigens in salivary gland tumours

MAM-3 and MAM-6 antigens of human milk fat globule membrane were detected immunohistochemically in 93 cases of salivary gland tumours as well as in normal glands. The antigens were visualized in 10% formalin-fixed paraffin sections. MAM-3 (MoAbs 115G3, 67D11) antigen was distributed in intercalated and striated duct cells of the normal salivary glands, and in luminal tumour cells and squamous metaplastic cells of pleomorphic adenomas. In pleomorphic adenomas the frequency of positive staining with MoAb 67D11 (54/67; 80.6%) was higher than that with MoAb 115G3 (36/67; 53.7%). MAM-6 (MoAbs 115D8, 115F5) antigen was expressed in luminal and lateral borders of serous acinar cells and ductal of the normal glands, and also in luminal borders of tubulo-ductal and glandular structures of salivary gland tumours. Ductal basal cells were characterized by existence of positive staining for MAM-6 antigen, in adenolymphomas MAM-6 antigen was restricted to the basal tumour cells. Some mucous cells of mucoepidermoid tumours were stained specifically with MoAb 115G3, and epidermoid cells of mucoepidermoid carcinomas manifested MAM-6 antigen staining. Immunohistochemical localization of MAM-6 antigen resembled that of epithelial membrane antigen (EMA) detected with MoAb.

Acute and late disease induced by murine coronavirus, strain JHM, in a series of recombinant inbred strains between BALB/cHeA and STS/A mice

n Abstractn n To examine the genetic control of acute and late disease induced by a murine coronavirus, strain JHM (JHMV), BALB/cHeA, STS/A, F1 hybrids and 13 recombinant inbred (RI) strains between BALB/cHeA and STS/A mouse strains were inoculated intracerebrally with 100 pfu of JHMV. All the BALB/cHeA mice died within 2 weeks from acute encephalitis. In contrast, STS/A mice were shown to be partially resistant, with a mortality rate of 30%, longer survival times and lower rates of viral production. The mortality rates, survival times and viral titers of F1 hybrids and the RI strains varied, suggesting involvement of multiple genes. STS/A, F1 hybrid and RI mice surviving the acute infection occasionally developed severe paraparesis about 1 month post-infection. In these mice, vacuolar degeneration, astrocytosis, the absence of perivascular cuffing and minimal demyelination were found in the central nervous system. No infectious virus could be recovered from these mice. Although the paralysis of delayed onset was limited to STS/A, F1 hybrid and eight of the 13 RI strains, the incidence varied significantly among the RI strains. These results may suggest that JHMV-induced late disease is also under multifactorial control. The pathogenesis of JHMV infection is discussed.n n