A serum test for cystic fibrosis using monoclonal antibody 19-9

Methodology and Applications of Disease Biomarker Identification in Human Serum

Biomarkers are biomolecules that serve as indicators of biological and pathological processes, or physiological and pharmacological responses to a drug treatment. Because of the high abundance of albumin and heterogeneity of plasma lipoproteins and glycoproteins, biomarkers are difficult to identify in human serum. Due to the clinical significance the identification of disease biomarkers in serum holds great promise for personalized medicine, especially for disease diagnosis and prognosis. This review summarizes some common and emerging proteomics techniques utilized in the separation of serum samples and identification of disease signatures. The practical application of each protein separation or identification technique is analyzed using specific examples. Biomarkers of cancers of prostate, breast, ovary, and lung in human serum have been reviewed, as well as those of heart disease, arthritis, asthma, and cystic fibrosis. Despite the advancement of technology few biomarkers have been approved by the Food and Drug Administration for disease diagnosis and prognosis due to the complexity of structure and function of protein biomarkers and lack of high sensitivity, specificity, and reproducibility for those putative biomarkers. The combination of different types of technologies and statistical analysis may provide more effective methods to identify and validate new disease biomarkers in blood.

How do we interpret an elevated carbohydrate antigen 19-9 level in asymptomatic subjects?

AIM

This prospective cohort study aimed to evaluate the etiology of elevated CA 19-9 levels and to present appropriate guidelines for the asymptomatic patients.

METHODS

Between January 2004 and March 2007, we enrolled consecutive asymptomatic patients who had elevated CA 19-9 levels >37 U/mL. To evaluate the etiology, the CA 19-9 level was rechecked and further studies were carried out. If the CA 19-9 level decreased to the normal range, or if it showed a decreasing trend, then it was monitored annually. Yet, if the CA 19-9 level showed an increasing trend, then the level was monitored at intervals of 1, 3, and 6 months until no evidence of malignancy was proven.

RESULTS

Of the 62,976 patients, 501 (0.8%) subjects showed an elevated CA 19-9 level. This prospective analysis was conducted on 353 subjects (70.5%) who were followed up for at least 6 months. Ten patients (2.8%) were diagnosed with malignancies. There were 97 patients (27.5%) with benign diseases and 246 patients (69.7%) were deemed non-specific.

CONCLUSIONS

CA 19-9 should not be used as a screening tool. In the case of a persistently elevated CA 19-9 level, further work-up for determining the etiology should be done.

Characteristics of pulmonary Mycobacterium avium-intracellulare complex (MAC) infection in comparison with those of tuberculosis

To clarify the clinical features of pulmonary Mycobacterium avium-intracellulare complex (MAC) infection, we retrospectively evaluated clinical manifestations, laboratory data, chest and maxillary sinus computed tomographic scans and induced sputum findings in 26 with MAC infection in comparison with 104 patients with tuberculosis (TB) infection. We found that carbohydrate antigen 19-9 (CA 19-9) and immunoglobulin A (IgA) in the serum and percentage of neutrophils in the sputum were significantly higher, and sinusitis was significantly more frequent in patients with MAC compared with patients with TB. MAC infection might be more strongly associated with impaired upper and lower airway defense mechanism in comparison with TB.

Human biliary mucin binds to E-selectin: a possible role in modulation of inflammation

E-selectin, expressed on endothelial cells, mediates adhesion of leukocytes and tumor cells to endothelium. CA19-9 (sialyl-Lewis(a)) and sialyl-Lewis(x) are specific ligands for E-selectin. We have recently shown that mucin-rich culture media from human gallbladder epithelial cells contains CA19-9. In this study, we have tested whether human biliary mucin binds to E-selectin. The ability of mucins to inhibit the adhesion of HL-60 cells to immobilized E-selectin was taken as an index for E-selectin binding. Gallbladder bile, hepatic bile, and culture medium from human gallbladder epithelial cells completely inhibited the adhesion of HL-60 cells to E-selectin. The mucin-rich fractions of human bile exhibited strong inhibition, whereas mucin-free fractions had little effect. In contrast to human bile samples, CA19-9-free medium from cultured dog gallbladder epithelial cells failed to inhibit HL-60 binding. Furthermore, after CA19-9 immunoaffinity chromatography, which selectively extracted CA19-9 from bile, bile samples showed poor inhibition of HL-60 adhesion to immobilized E-selectin. A good correlation was observed between E-selectin binding and CA 19-9 concentrations in bile. Our results show that human bile has E-selectin binding activity that is mediated by the CA19-9 side chain of biliary mucin.

Markers indicating deterioration of pulmonary Mycobacterium avium-intracellulare infection

To predict the natural history of pulmonary Mycobacterium avium-intracellulare (MAI) infection with nodular bronchiectasis, we retrospectively evaluated clinical manifestations, laboratory data, and bronchoalveolar lavage fluid (BALF) findings in 57 patients. The patients received follow-up chest computed tomographic scans and testing for sputum bacteriology between intervals of at least 12 mo. They were divided into two groups after observation for 28 +/- 13 mo: deteriorated (n = 34) and not-deteriorated (n = 23). There were no patients with spontaneous improvement. At the start of observation, the mean age was greater in the deteriorated group (69 +/- 9 yr) than in the not-deteriorated group (57 +/- 9 yr). The mean body-mass index was lower in the deteriorated group (19.2 +/- 3.1 kg/m(2)) than in the not-deteriorated group (21.5 +/- 1.5 kg/m(2)). C-reactive protein, erythrocyte sedimentation rate, and carbohydrate antigen 19-9 were significantly elevated in the deteriorated group. The BALF findings of the deteriorated group showed that the neutrophil cell counts were significantly increased. Thirty-four of 57 patients with pulmonary MAI infection with nodular bronchiectasis had progressive clinical and/or radiographic disease. The older and thinner patients tended to become worse. Neutrophil-related inflammation associated with a decrease in CD4+ lymphocyte might reflect the progression of pulmonary MAI infection with nodular bronchiectasis.

Attenuation of 19-9 antigen secretion in human colorectal carcinoma cell cultures by transfection with cDNA encoding novel ADP-ribosylation factor-like proteins

We have used cDNAs coding for novel ADP-ribosylation factor-like molecules (ARL184 and ARL184Delta) to alter 19-9 antigen glycoprotein secretion in cultured human colorectal carcinoma cells SW1116 by transfection and cloning. This ARL contains a lipophilic N-terminal with an isoleucyl and 3 leucyl residues, 4 functioning consensus sequence GTP binding sites, and 184 total aminoacyl residues. An ARL cDNA was also constructed deleting the codon for the N-terminal glycyl moiety. The resulting cell clones were shown by Northern blots to overexpress ARL mRNA. Electron microscopy-immunocytochemistry also indicated the overexpression of ARL granules subcellularly. Secretion of the tumor-associated 19-9 antigen into apical medium was decreased 3- to 5-fold and the secretion of TCA/PTA precipitable 3H-labeled glycoprotein was decreased by 34% in clone SW1116(ARL184)Delta. Western blot analyses of cell homogenates and media were in agreement with the secretion assays and showed a diminution of 170-200 kDa, 19-9, antigenicity in transfected cells and their media. Apical secretion of 19-9 antigen was diminished 14-fold in cells, SW1116 (ARL184)alpha, transfected with the complete ARL cDNA sequence, suggesting that the glycyl moiety may be required for maximal abatement. However, incorporation of label from [3H]myristate into 22-kDa bands of NP-40 extracts and ARL-antigenic molecules of parent cells was 3-fold greater than that in samples from the two transfectants; thus the transfected cells may not myristylate the overexpressed ARL efficiently. Notwithstanding the N-terminal glycyl moiety undergoing some other modification, we conclude that overexpression of this ARL is sufficient to generate a 19-9-deficient phenotype. These ARLs may eventually disrupt terminal oligosaccharide glycosylation, resulting in an apparent diminished exocytosis of 19-9 glycoprotein carriers by transfected and cloned cells.

Immunohistochemical detection of carbohydrate determinant 19-9 (CA 19-9) in intracranial epidermoid and dermoid cysts

We evaluated carbohydrate antigen (CA) 19-9 levels of intracranial dermoid and epidermoid cyst in serum and intratumoral tissue. The preoperative serum levels were mildly to moderately higher than their normal ranges in four of seven patients. In four patients with high serum CA 19-9 levels, they returned to normal ranges in three who had the cyst resected totally and remained slightly high in one with residual cyst. Immunohistochemical studies using anti-CA 19-9 antibody demonstrated positively stained capsule and keratinous tissue. Serum CA 19-9 levels of intracranial dermoid or epidermoid cysts with more teratomatous components may be elevated above normal levels.

Elevation of tumor-associated carbohydrate antigens in patients with diffuse panbronchiolitis

We investigated the serum levels of the tumor-associated carbohydrate antigens sialyl SSEA-1 (SLX) and sialyl Lewis(a) (CA19-9) in patients with diffuse panbronchiolitis (DPB) and other nonmalignant lung diseases. Both antigens were high in the serum and bronchoalveolar lavage fluid (BALF) of patients with DPB, bronchiectasis (BE), idiopathic pulmonary fibrosis (IPF), and interstitial pneumonia associated with collagen vascular disease (CVD). Markedly high levels of the antigens were demonstrated in the serum and BALF from patients with DPB. An immunohistochemical study of open-lung biopsy specimens from patients with DPB indicated that these antigens were selectively expressed on the bronchiolar epithelial cells and mucinous exudates in airspaces. Low-dose, long-term erythromycin (EM) treatment was recently reported to be effective for DPB, and we investigated its influence on serum and BALF antigen levels in DPB patients. Antigen levels in both serum and BALF decreased after EM treatment, with improvement of symptoms and laboratory data, and there was a significant correlation between the reduction in the SLX level in serum and neutrophil percentage in BALF pre- and post-EM treatment. Our result suggests that secreted carbohydrate antigens from the bronchiolar epithelium in DPB may appear in the serum as a result of airway damage in the lower respiratory tract, and serum levels of the antigens may be decreased by a reduction in neutrophils in BALF after EM treatment.

Changes in the CA 19-9 antigen and Lewis blood group with pulmonary disease severity in cystic fibrosis

The altered carbohydrate structure of sputum from patients with cystic fibrosis (CF) has been thought to be due to the inflammatory airway response. Carcinoembryonic antigen (CEA) and CA 19-9 detect sialosylated carbohydrates in mucus. The epitope of CA 19-9 is part of the Lewis A (Le(a)) blood group antigen. Serum concentrations of CEA and CA 19-9 were determined by radioimmunoassay in 41 CF patients, aged 6-34 years; 16 were asymptomatic Outpatients, and 25 had been admitted for pulmonary exacerbations. There was no difference in CEA between groups. The CA 19-9 serum concentration was elevated in 90% of patients who had at least one of the two Lewis antigens. The CA 19-9 concentration of Inpatients with exacerbations was 2.7 times that of stable Outpatients (263 +/- 44 versus 99 +/- 13 U/mL; P less than 0.02). CA 19-9 correlated significantly with age (r = 0.35, P less than 0.05), Brasfield score (r = 0.39, P less than 0.015), pulmonary function tests, cough severity (r = 0.50, P less than 0.001) and NIH clinical score (r = 0.57, P less than 0.001). CA 19-9 concentration of Inpatients decreased by 44% from admission to discharge (302 +/- 45 to 169 +/- 39, P less than 0.02). Fourteen of 25 (56%) of the Inpatients were Le(a) positive versus only 3/15 (20%) of Outpatients who had milder lung disease (P less than 0.002). Of the Inpatients, 25% with more advanced lung disease were Le(a+b+), a rare blood group in the normal population, and one not observed in the Outpatients with milder disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple potassium and chloride channels in the human colon carcinoma cell line SW1116

SW1116 cells have a profound capacity for secreting mucin molecules bearing the Lewisa epitope. Mucin molecules with the same epitope have been found to be elevated in the serum of patients with cystic fibrosis, a disease with defective ion channels. We therefore decided to study ion channels in this cell line. In the present work, we report the presence of two K(+)-channels and two Cl(-)-channels in the apical membrane of SW1116 cells. One of the K(+)-channels has a large conductance (approximately 278 pS), anomalous rectifying properties, and is inactivated rapidly. The second type exhibited a linear I/V curve (19 pS), was voltage insensitive and inactivation was not observed. In cell-attached patches, spontaneous openings of chloride channels were seen with higher frequency than previously reported in other colon carcinoma cell lines or airway epithelial cells. Inside-out experiments allowed identification of two different Cl(-)-channels (Cl(-)-1 and Cl(-)-2). Both exhibited rectification, but in opposite directions, and both were insensitive to NIPAB.

Isolation and characterization of mucin from the serum of cystic fibrosis patients

Using monoclonal antibody 19-9, elevated levels of the sialyl Lea antigen (NeuAc alpha 2-3Gal beta 1-3[Fuc alpha 1-4]GlcNac beta 1-3R) are detected in serum from most cystic fibrosis patients. We now report further characterization of the serum antigen and evidence that it is on a mucin glycoprotein and not on glycolipids. The antigen has an apparent molecular weight greater than 2 X 10(6) by gel filtration on Sephacryl S-400. On density gradient centrifugation, the antigen has a density of 1.54 g/ml in cesium chloride and 1.42 g/ml in cesium chloride/4 M guanidine HCl. Immunostaining with monoclonal antibody 19-9 of lipid extracts from cystic fibrosis patient serum and erythrocytes does not detect any antigen on glycolipids. The antigen was purified by gel filtration and density gradient centrifugation. After tritium labeling of the sialic acid residues, sodium dodecyl sulfate gel electrophoresis separates two subunits with apparent molecular weights of 200,000 and 400,000. All of the labeled sialic acid is released as low molecular weight oligosaccharides after mild alkaline borohydride degradation. The purified antigen contains fucose, galactosamine, glucosamine, and galactose but no mannose and is enriched in the amino acids threonine, serine, glycine, proline, and alanine. The purified antigen binds several antibodies recognizing epitopes common to many mucins. Thus, the physical, biochemical, and immunochemical properties of the purified antigen indicate that the sialyl Lea antigen is present on mucins in the serum of cystic fibrosis patients.

Identification of the peanut-agglutinin binding pancreatic cancer serum marker in pancreatic tissue extracts

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Enzyme-linked PNA lectin binding assay compared with CA19-9 and CEA radioimmunoassay as a diagnostic blood test for pancreatic cancer

Previous studies have shown that sera from patients with pancreatic cancer often contain a mucus glycoprotein that expresses the oncofetal antigen galactose 1-3, N-acetyl galactosamine, which is the T blood group antigen and the binding site for the lectin peanut agglutinin (PNA). An enzyme-linked lectin assay has been developed to quantify PNA-binding glycoproteins in serum and has been evaluated as a serological test for pancreatic cancer. Sera were studied from 53 patients with pancreatic cancer and 154 controls, including benign obstructive jaundice, acute and chronic pancreatitis, chronic liver disease and inflammatory bowel disease. The enzyme-linked peanut lectin assay proved highly reproducible and has 77% sensitivity and 83% specificity for pancreatic cancer, results that are very similar to those achieved in the same sera by CA19-9 radioimmunoassay (75% sensitivity, 82% specificity with the upper limit of normal set at 37 u ml-1). CEA assay proved less useful (60% sensitivity, 47% specificity). In this study better results were obtained if an upper limit of normal of 50 u ml-1 was used for CA19-9 (75% sensitivity, 92% specificity). Combination of CA19-9 assay with the upper limit set at 50 u ml-1 and the peanut lectin assay improved the sensitivity to 85% with only a slight fall in specificity (85%). These results compare well with published results for ultrasound and CT scanning.

CEA and CA 19-9 in benign pulmonary or mediastinal cystic lesions

Serum carbohydrate antigen (CA) 19-9 was present at high levels in pulmonary sequestration, mediastinal bronchogenic cysts, and mediastinal mature teratomas. The fluid in the cysts of the lesions contained a high level of CA 19-9. After operation, the titer of serum CA 19-9 returned to normal ranges. Histological studies showed that mucosal epithelium stained positively for CA 19-9. We speculate that CA 19-9 concentrated in the cystic lesion might flow into the peripheral blood. Carcinoembryonic antigen (CEA) was also present at high levels in the cyst fluid. CEA was positively stained in the epithelial cells using a polyclonal antibody but not a monoclonal antibody. The CEA detected at high concentration in the fluid was considered to be immunologically cross-reacting CEA.

The chemical basis for expression of the sialyl-Le(a) antigen

The SLe(a) antigen, originally defined by monoclonal antibody 19-9, is a complex carbohydrate epitope that differs from the normal human blood group Lea antigen only by the presence of an additional sialic acid residue. SLe(a)-active oligosaccharides occur in both gangliosides and mucin-like glycoproteins in developing embryonic gut, as well as in many normal adult glandular tissues and secretions, but the antigen is virtually absent from normal adult gastrointestinal lumenal epithelial cells. Following malignant transformation of adult gastrointestinal lining epithelium and many other endodermally-derived glandular epithelia, SLe(a)-active mucins released from the ensuing tumor appear in blood plasma. The level of circulating SLe(a) antigen is currently being investigated as a means of following tumor recurrence, progression, and therapy. Recent studies on the biosynthesis of SLe(a) explain the observations that, 1) the antigen does not occur in individuals of Le(a-b-) blood group, and 2) individuals that belong to the Le(a+b-) blood group express SLe(a) more strongly than Le(a-b+) individuals. Further, the biosynthetic studies predict a new tumor antigen, NeuAc alpha 2-3Gal beta 1-3GlcNAc beta 1.... (the immediate precursor to SLe(a)) that should be expressed in Le(a-b-) individuals in nearly the same tissue distribution as found for the SLe(a) antigen in Le(a+b-) and Le(a-b+) individuals. Based upon studies of SLe(a) expression in normal saliva and the pathway for biosynthesis of SLe(a), it seems likely that future clinical studies could be profitably directed towards improving the predictive value of the plasma SLe(a) level by adjusting the quantitative results according to the Lewis blood group and ABH secretor phenotype of the individual patient.

III6NeuAcLc4Cer in human SW1116 colorectal carcinoma cells: a possible oncofetal antigen that is not dependent on Lewis gene expression

Monospecific rabbit antibodies directed against the human milk sialyloligosaccharides III6NeuAcLcOse4 (sialyltetrasaccharide b), IV3NeuAcLcOse4 (sialyltetrasaccharide a), and IV6NeuAcnLc4Ose (sialyltetrasaccharide c) were used to detect their homologous haptens as gangliosides or ganglioside-derived sialyloligosaccharides from the human colorectal carcinoma cell line SW1116. III6NeuAcLc4Cer was first detected in human meconium [P. A. Prieto and D. F. Smith (1985) Arch. Biochem. Biophys. 241, 281-289], and its presence in a total ganglioside fraction of SW1116 cells together with its absence from a total lipid extract of normal human intestinal mucosa are consistent with III6NeuAcLc4Cer being a tumor-associated oncofetal antigen. IV3NeuAcLc4Cer, a ganglioside in human meconium [P. A. Prieto and D. F. Smith (1986) Arch. Biochem. Biophys. 249, 243-253], was also detected in SW1116 cells; an observation that is consistent with its being the immediate precursor to the sialyl-Lea ganglioside in SW1116 cells. Specific antisera against sialylated type 1 oligosaccharide chains whose expression is independent of the Lewis gene fucosyltransferase may be useful diagnostic reagents for oncofetal, carbohydrate antigens.

Monoclonal antibody CC3C195, which detects cancer-associated antigens in serum, binds to the human Lea blood group antigen and to its sialylated derivative

Mouse monoclonal antibody CC3C195, which detects elevated levels of its antigen in sera from many patients with colon and pancreatic cancer, binds with high affinity to the sialylated human Lea blood group antigen NeuAc alpha 2-3Gal beta 1-3 [Fuc alpha 1-4]GlcNac . . . and with lower affinity to the Lea blood group antigen itself.

A new ganglioside in human meconium detected with antiserum against human milk sialyltetrasaccharide a

Antiserum directed against the alditol derivative of the human milk monosialyloligosaccharide sialyltetrasaccharide a [D. F. Smith, P. A. Prieto, and B. V. Torres (1985) Arch. Biochem. Biophys. 241, 298-303] is used to detect a new ganglioside in human meconium by direct binding on nitrocellulose filters of the sialyl[3H]oligosaccharide alditol obtained from gangliosides after ozonolysis and alkali fragmentation. The sialyl[3H]oligosaccharide is purified by affinity chromatography on a column containing anti-sialyltetrasaccharide a antibodies. The affinity-purified sialyl[3H]oligosaccharide cochromatographs with the 3H-labeled alditol derivative of authentic sialyltetrasaccharide a from human milk. Results of sequential enzyme degradation of the pure sialyl[3H]oligosaccharide and cochromatography of the digestion products with standards are consistent with the presence in meconium of a monosialylganglioside with the structure NeuAc alpha 2-3Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc-ceramide. This ganglioside is presumably the biosynthetic precursor of the sialyl-Lea ganglioside [G. C. Hansson and D. Zopf (1985) J. Biol. Chem. 260, 9388-9392], which is also a component of human meconium.