Mouse monoclonal IgM antibody against human lung cancer line SK-LC-3 with specificity for H(O) blood group antigen

Peptide-displaying phage technology in glycobiology

Phage display technology is an emerging drug discovery tool. Using that approach, short peptides that mimic part of a carbohydrate's conformation are selected by screening a peptide-displaying phage library with anti-carbohydrate antibodies. Chemically synthesized peptides with an identified sequence have been used as an alternative ligand to carbohydrate-binding proteins. These peptides represent research tools useful to assay the activities of glycosyltransferases and/or sulfotransferases or to inhibit the carbohydrate-dependent binding of proteins in vitro and in vivo. Peptides can also serve as immunogens to raise anti-carbohydrate antibodies in vivo in animals. Phage display has also been used in single-chain antibody technology by inserting an immunoglobulin's variable region sequence into the phage. A single-chain antibody library can then be screened with a carbohydrate antigen as the target, resulting in a recombinant anti-carbohydrate antibody with high affinity to the antigen. This review provides examples of successful applications of peptide-displaying phage technology to glycobiology. Such an approach should benefit translational research by supplying carbohydrate-mimetic peptides and carbohydrate-binding polypeptides.

Immunohistochemical analysis of the poorly differentiated stomach adenocarcinoma with medullary growth pattern

Poorly differentiated gastric adenocarcinoma with medullary features (poor medullary) is distinguished by a propensity for hepatic metastasis. To classify it antigenically, we compared it to poorly differentiated adenocarcinoma with scirrhous growth pattern (poor scirrhous), well and moderately differentiated adenocarcinoma (differentiated adenocarcinoma), and normal gastric mucosa (foveolar and deep epithelium) using immunohistochemistry with antibodies against CEA, AFP, NSE, and Lewis-type antigens. Lewis(a) antigen was significantly associated with differentiated adenocarcinoma and foveolar epithelium, although Lewis(x) antigen was significantly expressed in poor medullary, poor scirrhous, and deep gland epithelium. From the viewpoint of expression of Lewis(a), there was no significant differentiation between poor medullary and differentiated adenocarcinoma, but it was definite between poor scirrhous and differentiated adenocarcinoma. Therefore, we conclude that in antigenic expression, poor medullary carcinoma is allied with differentiated adenocarcinoma rather than poorly differentiated scirrhous carcinoma.

Serological and immunochemical analysis of Lewis y (Ley) blood group antigen expression in epithelial ovarian cancer

The expression of Ley blood group antigen in epithelial ovarian cancer tissues and cell lines has been studied using a Ley-specific monoclonal antibody (MAb 3S193). In ovarian cancer specimens, Ley was expressed in 75% of the 140 tumor specimens examined, with strong or moderate expression being observed in 56% of the samples. Seven of the 11 ovarian cancer cell lines studied were Ley-positive. Using immunochemical approaches, Ley epitopes were found to be expressed on 4 types of carrier molecules: CA125 ovarian cancer antigen, MUC-1 mucins, lower m.w. glycoproteins and glycolipids. In cell lines, Ley was more commonly expressed on MUC-1 mucin than on CA125, whereas in tumor specimens Ley was commonly found on both CA125 and MUC-1. The biochemical nature of the smaller Ley glycoproteins was not determined, but it was shown that they were not CEA and LAMP-1, known Ley carriers in some other tumor types. Glycolipids carrying Ley epitopes were detected in both ovarian cancer cell lines and tumor specimens. The presence of Ley epitopes on a number of different molecular carriers, including 2 major ovarian cancer antigens (CA125 and MUC-1), explains the high incidence of Ley in ovarian cancer. The high expression of Ley in ovarian cancer and the availability of specific murine and humanized MAbs make Ley an attractive candidate target for clinical studies.

Expression of blood group-related antigens in normal and malignant pancreatic tissue correlated with genotype of the patient defined by saliva glycoprotein

BACKGROUND

Seven murine monoclonal antibodies (MoAb) detecting blood group antigens of the Lewis system and their sialylated derivatives were used to define their immunohistochemical distribution in normal and malignant pancreatic tissues. The specific blood group antigens studied included Lewis(a) (Le(a)), Lewisb (Leb), Lewisx (Le(x)), Lewis(y) (Le(y)), sialyl-Lewis(a) (s-Le(a)), sialyl-lacto-N-tetraose (s-LNT), and sialyl-Lewisx (s-Le(x)).

METHODS

The expression of these antigens was analyzed by immunoperoxidase technique in pancreatic tissue of patients with (n = 27) and without (n = 19) pancreatic cancer. The genetic background of their secretor status and their Lewis phenotypes were determined by the enzyme-linked immunosorbent assay using purified salivary glycoprotein and MoAb against eight different blood group-related antigens (Le(a), Leb, Le(x), Le(y), H1, H2, A, B2), and the putative genotypes of the patients were classified as follows: SeLe, Sele, seLe, and sele.

RESULTS

The following results were obtained: (1) In normal pancreas, Le(a), s-Le(a), s-LNT, and s-Le(x) were expressed in ducts, but their expression was restricted to the luminal side of the cytoplasm (cytoplasmic type with positive polarity). Leb and Le(y) showed similar patterns of expression in ducts and some parts of the acinus. In contrast, Le(x) was absent in most cases. (2) Expression of Leb was observed in normal pancreatic ducts in all 46 patients, regardless of their genotypes. Le(a) and s-Le(a) were not expressed in specimens from patients with the seLe and sele saliva phenotypes. (3) In pancreatic cancer, the following antigens were expressed cytoplasmically in the proportion of cases indicated: Le(a) (78%), Leb (85%), Le(x) (33%), Le(y) (44%), s-Le(a) (78%), s-LNT (89%), and s-Le(x) (85%). They also were detected in the surrounding stroma. This pattern of expression is distinct from that found in normal pancreatic tissue. Patients with Sele and sele genotypes did not express Le(a) or s-Le(a), except in one case. (4) Serum levels of carbohydrate antigen 19-9 (CA 19-9) were not elevated in patients with pancreatic cancer with the Sele and sele genotypes but were elevated in most patients with SeLe and seLe genotypes.

CONCLUSION

The overall findings indicate that Lewis-related antigens act as pancreatic tissue-related antigens, depending in part on salivary phenotypes of the patient. With proper antigen selection and the determination of secretor status, these anti-blood group MoAb may be of clinical utility in the diagnosis of pancreatic cancer.

Cell-surface antigens of human lung tumors detected by mouse monoclonal antibodies: definition of blood-group- and non-blood-group-related antigenic systems

The pattern of antigen expression in human non-small-cell cancers of various histological subtypes has been studied. Mouse monoclonal antibodies (MAbs) were generated following immunizations with cell lines of squamous, adeno- and anaplastic large-cell carcinomas of the lung. Seven non-blood-group-related antigens were defined in addition to 5 antigens related to blood-group determinants. Detailed specificity was established with a large panel of cultured cell lines and normal and neoplastic tissues. MAb F-18 reacted in direct tests with the immunizing squamous lung carcinoma cell line, with 5 out of 5 choriocarcinoma cell lines, but with no other cell lines. No expression of F-18 antigen was observed in any normal or malignant tissue examined. The other 6 non-blood-group-reactive MAbs (F-7, F-8, F-11, F-15, F-16 and F-17) could be distinguished by their reactivity on a panel of cultured cells and tissues. One MAb in this group (F-17) reacted strongly with 19/35 lung tumor cell lines, 32/76 other tumor-derived cell lines, cultured normal kidney cells and fetal lung fibroblasts. This antibody did not react with any normal adult tissues examined, but did react with several cancer tissues including 1/17 lung tumors, 2/4 ovarian cancers and 1/5 colon tumors. Immunoprecipitation tests revealed that 5 of the antigens were glycoproteins: F-18 (Mr greater than 200,000), F-15 (Mr 44,000), F-16 (Mr 90,000), F-17 (Mr 95,000) and F-8 (Mr 95,000). Four MAbs detected Y blood-group antigen (Le(y)), only 2 of which were able to agglutinate O erythrocytes. Another antibody detected X blood-group antigen (Le(x)).

Analysis of the fine specificities of 11 mouse monoclonal antibodies reactive with type 2 blood group determinants

The specificity of 11 mouse monoclonal antibodies reacting selectively with type 2 blood group structures was analyzed in detail by studying their reactivities with a panel of standard glycolipids, glycolipids from erythrocytes and blood group glycoproteins. The antibodies reacted with monofucosyl type 2 H, difucosyl type 2 structures (Le gamma) or both; none of the antibodies reacted with type 1 (H, Lea, or Leb) structures. Only a small proportion of the antibodies were completely specific for either type 2H or Le gamma structures. None of the antibodies had identical patterns of reactivity and their specificities were individually distinct. Seven antibodies preferentially agglutinated O and A2 erythrocytes. Anti-Le gamma-specific antibodies, except mAb101, did not agglutinate erythrocytes or react with glycolipids from erythrocytes, indicating the absence of Le gamma structures in erythrocyte glycolipids. The ability of some antibodies to react with A erythrocytes was shown to be due to cross-reactivity of the antibodies with type 3 (repetitive) A structures. The study demonstrates that monoclonal anti-carbohydrate antibodies tend to react with a range of related, and even distantly related, structure in a pattern characteristic of each antibody and that very few antibodies have extremely restricted specificities.

Expression of Lewis(a), Lewis(b), and sialated Lewis(a) antigens in early and advanced human gastric cancers

An immunohistochemical analysis of the expression of Lewis(a), Lewis(b), and sialated Lewis(a) blood group antigens was performed on specimens of human non-involved stomach (n = 91), early gastric cancers (n = 41), and advanced gastric cancers (n = 50). In non-involved stomach, Lewis(a) and Lewis(b) were detected mainly in surface epithelium, although sialated Lewis(a) was scarcely expressed. These blood group-related antigens were rarely observed in deep glands. In gastric cancers, Lewis(a) showed a tendency to be expressed in well or moderately differentiated carcinomas, and this was observed to be more marked in advanced tumors. There was no obvious difference in positive ratios of Lewis(b) between degrees of differentiation of the cancers. Sialated Lewis(a) was not detected in early cancers, and its frequent expression in well- or moderately differentiated, advanced carcinomas suggested an association with both cancer differentiation and progression. These results indicate that knowledge of the expression of blood group antigens may help interpret the antigenic alterations occurring in the course of carcinogenesis, differentiation, and progression of gastric cancers.

Immunohistochemical studies of blood group substance H in colorectal tumors using a monoclonal antibody

With the use of a murine monoclonal antibody with specificity for human blood group substance H, the distribution of this antigen on colorectal carcinomas and adenomatous polyps has been studied by immunohistochemistry. All of the 20 carcinomas studied were found to express H substance regardless of their location in the colon, their pathologic grade, or their clinical stage. Adenomas were variably positive for H substance, and expression of the antigen appeared to correlate with the degree of dysplasia seen on microscopic examination. Normal colonic mucosa, nonadenomatous polyps, and nonepithelial colonic neoplasms studied failed to express H substance. The results suggest that detection of H substance expression may be useful in the diagnosis of colonic malignancies and dysplastic premalignant lesions.

Blood group isoantigens ABO (H) in transitional carcinoma of the bladder: a clinicopathological study

Blood group A, B and H antigens were investigated in 183 paraffin embedded biopsies from 58 patients with transitional cell carcinoma of the urinary bladder, by a modified specific red cell adherence test, direct immunofluorescence with Ulex Europeus lectin and indirect immunoperoxidase method with monoclonal antibodies against blood group antigens. The results were correlated with pathological grade and stage and with the clinical course of patients evaluating the recurrence index and clinical state. Histological findings were roughly correlated with the expression of red cell tissue antigens but not with the presence of precursor H substance in biopsies from patients of blood group A or B, in which a higher proportion of H positive results was appreciated. The clinical course was also related to the presence or absence of blood group antigens in referential biopsies: 90 per cent of negative biopsies corresponded to patients who had high recurrence index whereas 75 per cent of positive biopsies corresponded to patients who had low recurrence index or did not have recurrence for five years; 25 per cent of recurrences observed in patients with referential positive biopsy were invasive whereas the proportion of invasive tumor in recurrence from negative biopsies rises to 73 per cent. In addition, all the final biopsies from patients who died of bladder tumor were negative for blood group antigens. The diagnostic and prognostic significance of these tissue antigens in transitional cell carcinoma of the urinary bladder is discussed, and we conclude that the analysis of blood group antigens in bladder biopsies by established techniques is a useful tool in clinical pathology for the screening and followup of bladder tumors, as previously suggested.

Genetic and nongenetic control of the immune response of mice to a synthetic glycolipid, stearylisomaltotetraose

Evidence for genetic control of antibody response to stearylisomaltotetraose (ST-IM4), a chemically defined synthetic glycolipid, was studied in various mouse strains. Anti-glycolipid antibodies were induced by repeated injections of ST-IM4 in complete Freund's adjuvant. C57BL and CBA/J mice were found to be good responders, while A/J, SJL/J, and AKR/J mice were poor responders. Responsiveness is independent of the H-2 genotype since AKR/J and CBA/J mice share the same H-2 locus. In addition, B10.A and B10.PL mice developed antibody levels similar to those of C57BL. The immunoglobulin heavy-chain locus (IgCH) was also found not to control antibody levels to ST-IM4 since C57BL and SJL/J mice share the same IgCH allotype. In C58/J mice, wide variation in response was observed among individual mice. Study of the response to ST-IM4 in 12 breeder pairs from different family lines of the C58/J colony also indicated that the regulation of the immune response to ST-IM4 is apparently more complex than can be explained by single gene control. C58 mice, unlike many other strains, had very low preimmune titers.

Cell surface antigens of human trophoblast and choriocarcinoma defined by monoclonal antibodies

Six distinct cell surface antigens of human trophoblast and choriocarcinoma were defined with MAbs. The distribution of the antigens was determined by MHA assays on 150 tumor cell lines and normal cell cultures and by immunofluorescence tests with a wide range of normal adult and fetal tissues and a tumor panel. Antigen LK26 is expressed on all cultured choriocarcinoma, teratocarcinoma and renal cancer lines but is absent from most cell lines derived from other tumor types and from cultures of normal kidney epithelium and fibroblasts. LK26 expression in normal tissues is restricted to the trophoblast. No other adult or fetal tissue was found to express the antigen, but choriocarcinoma and teratocarcinoma tissues were LK26+. SV19 is expressed on cultured choriocarcinomas and teratocarcinomas and on subsets of breast and colon cancer lines, but not on 120 additional cultures tested. In tissues, SV19 is detected in normal placenta, mammary gland and colon epithelium as well as in tumors of breast, colon and lung. Two antibodies, AbSV63 and AbK8, react with PLAP and AbSV63 also reacts with the intestinal form of the enzyme. AbLK24 defines a heat-stable determinant present on choriocarcinoma and breast cancer cell lines but absent from most other cultured cells. It is expressed on a small range of normal and malignant epithelial tissues, including normal trophoblast, normal breast epithelium and urothelium and tumors derived from these tissues. One antigen, K66, showed a wide distribution on cultured epithelial cells but was not found in any normal or malignant tissue. Finally, S4, a previously described marker of normal and malignant kidney epithelial cells, was also expressed on the choriocarcinoma cell lines. Four of the antigens are glycoproteins that could be immunoprecipitated from radiolabelled extracts of choriocarcinoma cells: LK26 (Mr 35,000), SV19 (Mr 40,000), PLAP (Mr 68,000) and S4 (Mr 160,000). The highly restricted distribution of LK26, SV19, S4, and PLAP in normal tissues and their expression in tumors make these antigens potential diagnostic markers of gestational choriocarcinoma and germ-cell tumors and, possibly, targets for immunotherapy.

An antibody to human thymic Hassall's body epithelium recognizes a subset of blood group A antigens

TE-19, a mouse monoclonal antibody (mAb) against thymic Hassall's body epithelium, was investigated because of its cross-reactivity with human erythrocytes. Antibody TE-19 was found to react only with group A erythrocytes, though it reacted with Hassall's body epithelium from donors of all blood group phenotypes. TE-19 antibody bound preferentially to cells of subgroup A1, and reacted only weakly with A2 and Aint erythrocytes. Although it apparently bound to A antigen with both glycolipid and glycoprotein backbones, TE-19 antibody only reacted with A antigenic moieties containing long or branched chain structures. Analysis of TE-19 reactivity with erythrocyte membrane components using electroblotting and immunostaining techniques showed antibody reactivity with components migrating in the areas of band 4 X 5 and just ahead of the dye front, consistent with membrane glycolipid. It is possible that all human thymic Hassall's bodies contain epithelial cells which, irrespective of the donor's erythrocyte blood group, bear a carbohydrate antigen similar to A antigen.

Analysis of the expression of H, Lewis, X, Y and precursor blood group determinants in saliva and red cells using a panel of mouse monoclonal antibodies

Salivary glycoproteins from 33 normal individuals were analyzed with a panel of mouse monoclonal antibodies to H-1, H-2, Lea, Leb, X, Y and precursor blood group determinants. Samples from 19/33 individuals co-expressed Leb and Y-determinants (secretors) and 6/33 co-expressed Lea and X-determinants (non-secretors). Erythrocytes of these individuals were typed Le (a-b+) and Le (a + b-), respectively. In seven other salivas, only one specificity, either Lea, Leb, X or Y, was expressed and in one sample none of these determinants could be detected. Only one saliva sample expressed H-1 specificity and none expressed H-2 or type 1 precursor determinants. The absence of H-1 and H-2 structures in secretors and the resulting expression of difucosylated Leb and Y-structures is probably a tissue-specific trait of salivary gland secretions. The strict co-expression of Leb with Y and Lea with X supports the conclusion that only one 2-O-fucosyl-galactose transferase, which can fucosylate both type 1 and type 2 chains, exists in salivary glands. The finding that a number of individuals expressed neither X- nor Y-specificities was unexpected in view of previous work showing that the 3-O-fucosyl N-acetylglucosamine transferase involved in forming this structure is a ubiquitous enzyme. The individualistic expression of blood group phenotypes in tissues should be considered when the altered expression of blood groups in malignancy and other diseases is studied.

Cell surface antigens of human bladder cancer defined by mouse monoclonal antibodies

Mouse monoclonal antibodies were obtained by immunization with cultured human bladder cancer or lysates of bladder papilloma. They identify 11 distinct antigenic systems as defined by serological analysis of cultured cells and studies of antigen distribution in normal and neoplastic tissues. The most restricted of these antigens, Om5, defines a subset of bladder tumors. Om5 is not detected in normal bladder urothelium or in any other normal or malignant tissue. T101 and JP165 are also subset markers for bladder cancer that are not detected in normal tissues. T16, T43, T87, and J143 (antigens represented on many cultured cells) are found in specific areas of the normal urinary tract and in a distinctive range of other normal and malignant cell types--e.g., T16 expression in pluristratified epithelium of skin, exocervix, and esophagus. T138 antigen is also a common feature of cultured cell lines, but its expression in sections of normal tissues is restricted to endothelial cells. In contrast, T110 is poorly represented on cultured cells but can be detected in culture supernatants. Localization of T110 in normal tissues showed that it is a component of the extracellular matrix. All determinants detected by this series of antibodies are heat labile and not related to A, B, H, I, Lewis blood group antigens. Six of the antibodies immunoprecipitated glycoproteins from radiolabeled cell lysates: AbT16 (Mrs 48,000 and 42,000), AbT87 (Mr 60,000), AbT43 (Mr 85,000), AbJ143 (Mr 140,000, 120,000, 60,000), AbT43 (Mr 85,000), AbJ143 (Mr 140,000, 120,000, and 30,000), and AbT110 (Mr 240,000).

Monoclonal antibodies specific for two different histological types of human lung carcinoma

Hybridomas secreting monoclonal antibodies specific for human lung cancer were produced by fusing immunized mouse spleen cells with mouse myeloma line X63-Ag8.653. Prior to fusion, BALB/c mice were immunized with two different histological types of human lung cancer (Squamous cell carcinoma and adenocarcinoma) obtained from surgery. An immunocytoadherence test was used to select hybridomas secreting antibodies that bound the patient's lung tumor, but did not bind to a B-lymphoblastoid cell line derived from the same patient. Five stable antibody-producing hybrids have been established and cloned. The antibodies produced by these clones have been characterized according to their light and heavy chain isotypes and for their specificity. In addition to binding to the tumor used for immunization, the antibodies bound to other lung tumors of the same histological type (i.e., squamous cell or adenocarcinoma). This reactivity was observed with both established lung tumor cell lines and with fresh tumors obtained from biopsy of patients in our clinic. Some significant reactivity was also observed with large cell carcinoma but the antibodies did not react with small cell carcinomas of the lung, bronchiolo-alveolar cell carcinoma, cancer of the esophagus and stomach, melanomas, several types of leukemias, normal human lung tissue, fibroblasts, or erythrocytes of type A, B, or O. Two of the five antibodies, 5C7 and 5E8 cross-reacted with one breast cancer obtained from surgery, and 5C7 also cross-reacted with one melanoma biopsy specimen. These results suggest that we have generated monoclonal antibodies that recognize a set of antigenic determinants that are commonly expressed on a portion of human lung tumors that are not detectable on a variety of other human tumors or normal human tissue.

Monoclonal antibodies in urology

The recent development of hybridoma technology has made it possible to obtain large quantities of antibody against a single determinant (monoclonal antibodies). This review describes the history of hybridoma technology and the method of producing monoclonal antibodies. It examines the role of such antibodies in diagnosis, tissue typing, histochemistry, developmental biology and study and treatment of diseases, including cancer, emphasizing the work being done on urological diseases.

A marker of human foetal endoderm defined by a monoclonal antibody involves Type 1 blood group chains

This report demonstrates that a marker of human embryonic endoderm and embryonal carcinoma cells recognized by a hybridoma antibody FC 10.2, involves Type 1 blood group chains with the sequence Gal beta 1 leads to 3G1cNAc beta 1 leads to 3Gal beta 1 leads to 4G1c. This conclusion has been reached from antigenic analyses of meconium, ovarian cyst glycoproteins, oligosaccharides and glycolipids having Type 1 or Type 2 blood group chains. From knowledge of saccharide sequences and blood group related antigens in gastrointestinal tissues of man, we deduce that the 'disappearance' of FC 10.2 antigen from the normal, differentiated cells of the adult may result from masking by additional glycosylations or other substitutions.

Human erythrocyte antigens. Regulation of expression of a novel erythrocyte surface antigen by the inhibitor Lutheran In(Lu) gene

Our study describes a novel human erythrocyte protein antigen, the expression of which is regulated by the rare Lutheran inhibitor In(Lu) gene. We have produced a monoclonal antibody (A3D8) that bound strongly to erythrocytes from subjects with Lutheran phenotypes Lu(a+b+), Lu(a+b-), and Lu(a-b+) but bound negligibly to erythrocytes from subjects with the dominant form of Lu(a-b-) phenotype, reflecting inheritance of the In(Lu) gene. Importantly, erythrocytes from an individual with the recessive form of Lu(a-b-) phenotype (i.e., absence of the In(Lu) gene and absence of genes encoding for Lutheran antigens) showed reactivity with A3D8 antibody comparable to that seen with Lu(a+) or Lu(b+) erythrocytes. A3D8 antigen activity was also found on all leukocytes and in serum and plasma; this activity also appeared to be regulated by the In(Lu) gene in serum, plasma, and on a subset of leukocytes. Thus, we have identified a human erythrocyte protein whose expression is modified by the In(Lu) gene. This knowledge that such an antigen exists on erythrocytes and in normal plasma should allow further studies into the molecular genetics of the In(Lu) gene and into the functional and structural significance of the A3D8 antigen.

Marker of peripheral blood granulocytes and monocytes of man recognized by two monoclonal antibodies VEP8 and VEP9 involves the trisaccharide 3-fucosyl-N-acetyllactosamine

Two hybridoma antibodies (VEP8 and VEP9) raised against the promyelomonocytic leukemia cell line HL60 have previously been shown to distinguish human granulocytes and monocytes from other cells of the peripheral blood. We report here that both antibodies recognize the carbohydrate structure 3-fucosyl-N-acetyllactosamine with the following sequence: (formula; see text) This structure is the same as that recognized by a hybridoma antibody against mouse teratocarcinoma cells (anti-SSEA-1) which recognizes an early embryonic antigen in the mouse. Until recently this carbohydrate structure was considered to be rare among glycoproteins and glycosphingolipids. However, there is a growing list of human and animal glycoproteins in which this sequence has been detected by chemical and immunochemical methods. In this article we survey this information and discuss how this and other carbohydrate structures behave as differentiation- or tumor-associated antigens.

A monoclonal antibody against human colonic adenoma recognizes difucosylated Type-2-blood-group chains

A monoclonal antibody C14/1/46/10 showing preferential binding to membranes of human colorectal carcinomas over normal colon mucosae was obtained by immunization of mice with extra-nuclear membranes of a human colonic adenoma. Binding and inhibition of binding assays using blood cells or glycoproteins with known blood-group activities indicated that the antibody recognizes a carbohydrate antigen co-existing with the blood-group-H determinant: Fuc alpha 1 leads to 2 Gal. Inhibition assays with structurally defined oligosaccharides showed that the antigenic determinant involves difucosylated Type-2-blood-group chains with the structure: (formula; see text)

Mass spectrometry of a human tumor glycolipid antigen being defined by mouse monoclonal antibody NS-19-9

With an antibody-to-chromatogram binding assay to follow the preparation a glycolipid was isolated from human pancreatic carcinoma using a mouse monoclonal antibody of apparent specificity for gastrointestinal tumors. Direct probe mass spectrometry of three derivatives established the sugar sequence as NeuAc-hexose-(fucose)N-acetylhexosamine-hexose-hexose and the ceramide to be composed mainly of phytosphingosine and 16-24 carbon 2-hydroxy fatty acids. NMR spectroscopy of two of the derivatives made likely the presence of the sequence Gal beta 1 leads to 3GlcNAc(4 comes from 1 alpha Fuc)beta 1 leads to, which is the blood group Lewis a determinant. This is in agreement with recent results from degradation studies.