Histochemical demonstration of sugar residues by lectin and immunocytochemical techniques for blood group antigens in human colon

Bifidobacterium bifidum Extracellular Sialidase Enhances Adhesion to the Mucosal Surface and Supports Carbohydrate Assimilation

Bifidobacterium is a natural inhabitant of the human gastrointestinal (GI) tract. We studied the role of the extracellular sialidase (SiaBb2, 835 amino acids [aa]) from Bifidobacterium bifidum ATCC 15696 in mucosal surface adhesion and carbohydrate catabolism. Human milk oligosaccharides (HMOs) or porcine mucin oligosaccharides as the sole carbon source enhanced B. bifidum growth. This was impaired in a B. bifidum ATCC 15696 strain harboring a mutation in the siabb2 gene. Mutant cells in early to late exponential growth phase also showed decreased adhesion to human epithelial cells and porcine mucin relative to the wild-type strain. These results indicate that SiaBb2 removes sialic acid from HMOs and mucin for metabolic purposes and may promote bifidobacterial adhesion to the mucosal surface. To further characterize SiaBb2-mediated bacterial adhesion, we examined the binding of His-tagged recombinant SiaBb2 peptide to colonic mucins and found that His-SiaBb2 as well as a conserved sialidase domain peptide (aa 187 to 553, His-Sia) bound to porcine mucin and murine colonic sections. A glycoarray assay revealed that His-Sia bound to the α2,6-linked but not to the α2,3-linked sialic acid on sialyloligosaccharide and blood type A antigen [GalNAcα1-3(Fucα1-2)Galβ] at the nonreducing termini of sugar chains. These results suggest that the sialidase domain of SiaBb2 is responsible for this interaction and that the protein recognizes two distinct carbohydrate structures. Thus, SiaBb2 may be involved in Bifidobacterium-mucosal surface interactions as well as in the assimilation of a variety of sialylated carbohydrates.

Adhesion to the host mucosal surface and carbohydrate assimilation are important for bifidobacterium colonization and survival in the host gastrointestinal tract. In this study, we investigated the mechanistic basis for B. bifidum extracellular sialidase (SiaBb2)-mediated adhesion. SiaBb2 cleaved sialyl-human milk oligosaccharides and mucin glycans to produce oligosaccharides that supported B. bifidum growth. Moreover, SiaBb2 enhanced B. bifidum adhesion to mucosal surfaces via specific interactions with the α2,6 linkage of sialyloligosaccharide and blood type A antigen on mucin carbohydrates. These findings provide insight into the bifunctional role of SiaBb2 and the adhesion properties of B. bifidum strains.

Aberrant expression of histo-blood group A type 3 antigens in vascular endothelial cells in inflammatory sites

Histo-blood group ABH antigens are widely distributed in human tissues. The epitopes of ABH antigens are carried by at least four different peripheral core isotypes of internal carbohydrate backbones (type 1-4). Each type of ABH antigen is expressed tissue specifically, and aberrant expression of ABH antigens is often observed during oncogenesis. We immunohistochemically examined the expression of A type 3 antigens in wounded and diseased skin tissues (A and AB blood groups). In uninjured skin, the expression of A type 3 antigens was restricted to the eccrine sweat gland. In addition to the sweat glands, A type 3 antigens were found in vascular endothelial cells of the wound sites. The extent of A type 3 antigens expression related to postinfliction intervals. A significantly higher expression rate of A type 3 antigens in endothelial cells was also observed in diseased skin, suggesting that inflammation might induce A type 3 antigen expression in endothelial cells. Double-color immunofluorescence staining of the specimens showed that von Willebrand factor (vWF) was a core-protein of A type 3 determinants aberrantly expressed in endothelial cells in inflamed tissues, suggesting that aberrant expression of A type 3 antigens is involved in stabilization of vWF in inflammation.

Lactobacilli binding human A-antigen expressed in intestinal mucosa

Adherent lactic acid bacteria (LAB) in the human intestine were investigated using the surface plasmon resonance technique with the biosensor BIACORE-1000. Ninety-three LAB strains were isolated from human feces and evaluated for binding to human blood type-A antigen [GalNAcalpha1-3 (Fucalpha1-2) Gal-: A-trisaccharide] expressed in the intestinal mucosa. Eleven strains showed strong adherence to an A-trisaccharide biotinyl polymer (BP) probe, and slightly or no adherence to a B-trisaccharide BP probe. Four strains with high adherence (high A/B ratio) were selected and their surface layer proteins (SLPs) were evaluated for A-antigen ligand binding using BIACORE. The SLP from L. brevis strain OLL2772 showed a single band at ca. 48 kDa by SDS-PAGE analysis and it had a very strong adherence to the human A-antigen, as shown using an anti-A lectin blocking technique. A partial N-terminal sequence of the band showed strong homology to an S-layer protein of L. brevis ATCC8287T. The probiotic LAB binds to human blood type-A antigen expressed in the intestinal mucosa which may aid in colonization of the gut.

Comparison of the expression of ABH/Lewis-related antigens in polypoid and non-polypoid growth types of colorectal carcinoma

BACKGROUND AND AIMS

Colorectal tumors can be classified based on their growth pattern into the polypoid growth-type (PG-type) and non-polypoid growth-type (NPG-type). To ascertain whether there is any relationship between the expression of particular blood group-related antigens (A, B, H, Lewis (Le)a, sialyl Le(a), Le(x), sialyl Le(x)) in a colorectal tumor, and a tumor having polypoid or non-polypoid growth, we examined 78 PG-type and NPG-type colorectal cancers.

METHODS

Fourteen PG-type and 64 NPG-type colorectal carcinomas were subjected to immunohistochemical analyses by using monoclonal antibodies against A, B, H, Le(a), sialyl Le(a), Le(x) and sialyl Le(x).

RESULTS

The patients with NPG-type carcinomas had a significantly younger age of onset, significantly smaller maximal tumor diameter, significantly higher rate of lymph node metastasis and significantly worse prognosis than those with PG-type carcinomas. Among the 32 tumors of patients with blood type A or AB, isoantigen A was expressed in a significantly larger percentage of NPG-type carcinomas than PG-type carcinomas (95.8 vs 62.5%, respectively; P=0.014). Among all 78 tumors, sialyl Le(x) antigen was expressed in a significantly larger percentage of NPG-type than PG-type carcinomas (90.6 vs 64.3%, respectively; P=0.010). Multivariate analysis using the logistic regression model revealed that isoantigen A and sialyl Le(x) expression were independent predictive risk factors for the development of NPG-type colorectal carcinoma.

CONCLUSIONS

These data suggest that the expression of isoantigen A and sialyl Le(x) in a colorectal carcinoma partially determines whether the tumor will have polypoid or non-polypoid growth.

Lectin cytochemical characterization of the N- and O-linked oligosaccharides in the human rectum

The oligosaccharides of the mucus glycoproteins of the human rectum are important for the lubricant and protective role suggested for the rectal mucus. Changes in oligosaccharide composition are observed in several colon diseases, and some of these changes could be used as diagnostic and prognostic indicators. Thus, a previous knowledge of the normal mucus glycoproteins is necessary. The aim of the present study is the characterization of the oligosaccharides of the goblet cells and enterocytes of the human rectum. For this, a battery of 15 lectins, in combination with chemical and enzymatic deglycosylation procedures, was used. Our results suggest the presence of N-acetylglucosamine (GlcNAc), Man, Glc, N-acetylneuraminic acid (Neu5Ac)(alpha2-6)- and Neu5Ac(alpha2-3)-linked, N-acetylgalactosamine (GalNAc) and Gal(beta1-3)GalNAc in the oligosaccharides of the goblet cells. Moreover, N-linked oligosaccharides specifically contained Gal(beta1-4)GlcNAc, while AAA-positive Fuc was only detected in O-linked oligosaccharides. Some of these carbohydrates were only visualized after removal of N- or O-linked oligosaccharides, suggesting a high level of approximation between the oligosaccharide chains, that render the carbohydrate inaccessible to the lectins. Differences in the labelling pattern between the goblet cells of the surface epithelium and the upper half of the crypts, and those of the lower half of the crypts suggests a maturation process for the goblet cells, which modifies the oligosaccharide composition of the secreted glycoproteins, as they ascend throughout the crypts. This maturation process includes the incorporation of new carbohydrates (GlcNAc), and the masking (Neu5Ac(alpha2-3)-linked) or unmasking (Glc and GalNAc) of others.

Expression of H type 1 antigen of ABO histo-blood group in normal colon and aberrant expressions of H type 2 and H type 3/4 antigens in colon cancer

We have immunohistochemically examined the distribution of the H antigens of type 1, type 2 and type 3/4 chains of the ABO(H) histo-blood group system in human normal colon and in colon cancer using three monoclonal antibodies specific for each of the H type 1/2, H type 2, and the H type 3/4 chain. We unexpectedly found that mucosa of the normal colon from secretors but not that from nonsecretors expressed only H type 1 and did not express H type 2 or H type 3/4. The H type 1 was expressed in goblet cells. Positive goblet cells expressing H type 1 were decreased in number progressively from the proximal colon to the rectum. In tumors, 4 (57%) of 7 cancer tissues of the proximal colon from secretors expressed no H type 1, whereas all 8 cancer tissues of the distal colon from secretors expressed H type 1. The aberrant expressions of H type 2 and H type 3/4 (47 and 67%, respectively) were found in cancer tissues from both the proximal and the distal colon. Tumors from nonsecretors did not express any H antigens. Our results suggested that the expression of H type 1 in the normal colon and the aberrant expressions of H type 2 and H type 3/4 in colon cancer tissues were regulated by FUT2-encoded Se type alpha(1,2)fucosyltransferase. However, UEA-I-positive substance(s) rather than H type 2 were uniquely expressed throughout the normal colon and in colon cancers from both secretors and nonsecretors.

Expression of N-acetyllactosamine and beta1,4-galactosyltransferase (beta4GalT-I) during adenoma-carcinoma sequence in the human colorectum

We set out to determine the expression profiles of glycoproteins possessing N-acetyllactosamine, a precursor carbohydrate of sialyl Le(x), during colorectal cancer development. We immunohistochemically analyzed the distribution of N-acetyllactosamine as well as of beta4GalT-I, a member of the beta1, 4-galactosyltransferase family responsible for N-acetyllactosamine biosynthesis, in normal mucosa and in adenoma and carcinoma of the human colorectum. Using monoclonal antibody H11, N-acetyllactosamine was barely detectable in the normal mucosa. In low-grade adenoma, however, N-acetyllactosamine was weakly but definitely expressed on the cell surface, and its expression level was moderately increased in high-grade adenoma and markedly increased in carcinoma in situ as well as in advanced carcinoma. To detect beta4GalT-I, we used a newly developed polyclonal antibody (designated A18G), which is specific for the stem region of human beta4GalT-I. Faint expression of beta4GalT-I was detectable in normal mucosa, and the expression level was moderately increased in low-grade adenoma and in high-grade adenoma and markedly increased in carcinoma in situ and advanced carcinoma. The expression of N-acetyllactosamine was highly correlated with the expression of beta4GalT-I in these tumor cells. These results indicate that the expression level of beta4GalT-I is apparently enhanced during tumorigenesis in the colorectum and that beta4GalT-I mostly directs the carcinoma-associated expression of N-acetyllactosamine on the colorectal tumor cell surface. (J Histochem Cytochem 47:1593-1601, 1999)

Presence of H type 3/4 chains of ABO histo-blood group system in serous cells of human submandibular gland and regulation of their expression by the secretor gene (FUT2)

We have investigated by immunochemistry the distribution of H Type 3/4 chains of the ABO histo-blood group system in human submandibular gland using a monoclonal anti-H MBr1 antibody specific for H Type 3/4 chains, and have found the expression of H Type 3/4 chains was mainly in the serous cells. Serous cells from secretors were stained by MBr1 but not by anti-A and anti-B antibodies, whereas serous cells from nonsecretors exhibited a negative reaction with MBr1. Mucous cells were not stained by MBr1. Only a few striated duct cells showed a weak reaction with anti-H MBr1. These results suggested that the H Type 3/4 chains were distributed predominantly in the serous cells of the human submandibular gland and that secretor Type alpha(1,2)fucosyltransferase (Se enzyme) controlled the synthesis of H Type 3/4 chains in vivo. Saliva also contained H Type 3/4 chains, which were controlled by the secretor gene (FUT2). The differences in the distributions of H Type 1, H Type 2, and H Type 3/4 chains of the ABO histo blood group system in the submandibular gland are discussed.

Immunohistochemical expression of ABH/Lewis-related antigens in primary breast carcinomas and metastatic lymph node lesions

The expression of blood group antigens A, B, and H, as well as sialylated and nonsialylated forms of Lewis(a) and Lewis(x), was studied using immunohistochemical methods in normal and tumor tissues in the following cohort of patients: 51 patients with primary breast carcinoma, 13 with metastatic lymph node lesions, and 16 with benign tumors of the breast. As a control, normal tissue was obtained from a similar group of 22 patients with breast cancer. The noncancerous tissues expressed the same A/B/H antigens as the patients' red blood cells and also usually expressed Lewis-related antigens. Seventy-six percent of primary carcinomas failed to express the appropriate A/B/H antigens, and in one blood group A patient the tumor tissue expressed B antigen. In the metastatic lesions, Lewis(a)/sialyl Lewis(a) expression was reduced when compared with the primary tumors, but Lewis(x)/sialyl Lewis(x) antigens were still expressed. These results suggest a possible relationship between the metastatic behavior of the tumor and expression of the blood group antigens.

Monoclonal antibody recognizing a determinant on type 2 chain blood group A and B oligosaccharides detects oncodevelopmental changes in azoxymethane-induced rat colon tumors and human colon cancer cell lines

Altered expression of ABH blood group substances is a common feature of human colorectal carcinoma, yet it remains unclear how these structural changes influence the biological properties of tumor cells. Azoxymethane-induced rat colon tumors display many features of the human disease, thereby providing a potentially useful model to study the role of blood group substances in colon cancer progression. We have prepared monoclonal antibodies to a microsomal fraction isolated from an azoxymethane-induced rat colon tumor and selected an antibody that detects cancer-associated changes. Monoclonal antibody (mAb) 3A7 recognizes a determinant on type 2 chain blood group A (GalNAc alpha 1-3[Fuc alpha 1-2]Gal beta 1-4GlcNAc-R) and B (Gal alpha 1-3[Fuc alpha 1-2]Gal beta 1-4GlcNAc-R) oligosaccharides. Expression of the epitope detected by this antibody was developmentally regulated in rat colon, with maximal expression from day 4-21 after birth. Immunohistochemical staining and Western blotting analyses of azoxymethane-induced colon tumors revealed increased expression of the epitope in all of the 21 colonic tumors examined, including preneoplastic glands within transitional mucosa. Conventional and signet-ring adenocarcinomas that had invaded through the muscularis propria (Duke's B2) consistently showed the most intense staining with mAb 3A7, including regions depicting angioinvasion. Some of the lymph node metastases (Duke's C2) stained poorly with the antibody. The epitope was also expressed in blood group A positive human colon carcinoma cell lines, including HT29 and SW480 but not by SW620, a cell line derived from a lymph node metastasis isolated in vivo from the SW480 primary tumor, or in the blood group B cell line SW1417. The glycoproteins detected by mAb 3A7 in rat colon tumors and HT29 cells ranged in size between 50 and 200 kd, including a major species of 140 kd. Affinity chromatography of detergent lysates of normal rat colon on the blood group A specific lectin Dolichos biflorus (DBA)-agarose resulted in nearly quantitative binding of glycoprotein species detected by the antibody. By contrast, immunoreactive glycoproteins from rat colon tumors or HT29 cells bound poorly to DBA-agarose but were retained by another blood group A-binding lectin, Helix-pomatia (HPA)-agarose. These results indicate that colon carcinogenesis results in quantitative as well as qualitative changes in oligosaccharides detected by mAb 3A7 and suggest that the combined use of mAb 3A7 and blood group A-specific lectins may provide a useful tool for early detection of colon cancer.

Monoclonal antibody TKH2 to the cancer-associated epitope sialosyl Tn shows cross-reactivity with variants of normal colorectal goblet cell mucin

It has been suggested that synthesis of mucin-type carbohydrate chains may be arrested at the core structure Tn. This may occur following premature sialylation of Tn giving the structure STn. TKH2, a monoclonal antibody to STn, is regarded as showing highly specific reactivity with colorectal and other epithelial neoplasms. In this study we have shown that TKH2 cross-reacts with normal colorectal goblet cells that are mild PAS positive (specific for non-O-acetylated sialic acid). Approximately 9% of caucasians secrete colorectal mucin in which sialic acid is non-O-acetylated. TKH2 also cross-reacts with mild PAS negative colorectal goblet cells when sections have been pre-treated with potassium hydroxide (to remove O-acetyl groups from sialic acid). These findings make it likely that the usual non-reactivity evidenced by TKH2 for normal colorectal goblet cells is due to the presence of sialic acid that is heavily O-acetylated. The reactivity of TKH2 for colorectal cancer mucin can be readily explained by the loss of sialic acid O-acetyl substituents and not necessarily by incomplete synthesis of mucin-type carbohydrate chains.

Colorectal mucin histochemistry in health and disease: a critical review

Neoplastic, inflammatory and regenerative processes affecting colorectal mucosa are associated with alterations in structure of epithelial mucin. This review collates mucin-, lectin-, and immuno-histochemical observations on colorectal mucins and introduces recent molecular genetic insights into the structure of the protein backbone of mucins. The numerous structural modifications uncovered by the various technical approaches have been reduced to a few manageable principles that are of relevance to both researcher and diagnostic pathologist. Particular attention is drawn to the need to appreciate the limited specificities of probes, the confounding influences of anatomical site and genetic factors (necessitating the use of appropriate positive and negative control tissues) and the precise location of secretory material. In the past, insufficient attention has been given to the effects of altered differentiation including metaplasia and differing lineage expression in epithelial disorders of growth. It is likely that certain changes loosely ascribed to goblet cell mucin, such as neo-expression of blood group antigens and anomalous expression of core carbohydrate structures, do not occur at all. Critical examination of available data point to only two consistent and unequivocal changes affecting goblet cell mucin in pathological processes: loss of O-acetyl substituents at sialic acid C4 and C7,8,9 and increased sialylation. Furthermore, there are no neoplasia-specific alterations in mucins documented to date. All neoplasia-associated changes have been described in non-neoplastic lesions also.

Glycoconjugates of the normal human colorectum: a lectin histochemical study

Previous studies of the normal human colorectum by lectin histochemistry have used a mixture of tissues, including those derived from colons harbouring neoplasia and inflammatory bowel diseases. In the current investigation, tissues from patients without either of these conditions have been examined with a wide panel of lectins, encompassing specificities directed against both N- and O-linked sequences, using an avidin peroxidase revealing system and evaluated with a semiquantitative scoring method. The results of binding of these lectins have been compared with those seen in the resection margins of (at least 5 cm away from) colorectal carcinomas. Consistent regional variations were noted between right- and left-sided colonic tissues, with more diverse glycan structures and a greater sialyl content in the distal colon. There was evidence of graduation of formation of oligosaccharide chains in developing crypts, possibly related to the maturation and expression of glycosyl transferases responsible for the incorporation of mannose residues of N-linked oligosaccharides and of N-acetylgalactosamine and N-acetylglucosamine. Comparison with previous reports has revealed some variations, possibly related to tissue fixation and processing and to lectin concentrations employed, which raises the question of standardization of methodologies in lectin histochemical investigations.

Dolichos biflorus agglutinin binding in hereditary bowel cancer

Dolichos biflorus agglutinin (DBA) binds specifically to N-acetylgalactosamine (GalNAc), one of the 5 sugars contributing to the oligosaccharide component of human colorectal goblet cell mucin. DBA binds to goblet cells of the upper crypt and surface epithelium within the proximal colon and to the majority of goblet cells of the distal large bowel. DBA therefore serves as a marker of colorectal goblet cell differentiation with a distinct proximal to distal gradient effect. Previous reports indicate significant loss of DBA reactivity within morphologically normal colorectal mucosa derived from at-risk members of hereditary non-polyposis colorectal cancer (HNPCC) families. This finding could not be confirmed in the present study. Reduced binding was a relatively consistent finding in transitional mucosa, hyperplastic polyps and carcinoma, with adenomas displaying a more varied pattern of loss. Reduced binding by DBA may be explained by several mechanisms and may not necessarily reflect loss of GalNAc. The concept that lectins can be used to identify stepwise changes that occur during neoplastic evolution should not be accepted uncritically.

Immunohistochemical demonstration of glycoconjugates bearing the type 2 chain-backbone structure in human fetal, normal and neoplastic gastrointestinal tract

Immunohistochemical distributions of carbohydrate antigens based on the type 2 chain in normal as well as fetal and neoplastic tissues of human gastrointestinal tract were investigated with a monoclonal antibody (MAb) H11 (specific for type 2 chain) alone and in combination with the two MAbs MSG15 (for alpha 2----6 sialylated type 2 chain) and IB9 (for the alpha 2----6 sialylated type 2 chain and glycoproteins having NeuAc alpha 2----6Gal-NAc), and 188C1 (for short- and long-chain Lex antigens) and FH2 (for the long-chain Lex antigen). In the pyloric mucosa of secretors, the type 2 chain is oncodevelopmentally expressed, but in non-secretors it is detected in surface mucous cells of normal gastric mucosa. The alpha 2----6 sialylation, which is confined to endocrine cells of normal pyloric mucosa, occurs in fetal and carcinoma tissues. Irrespective of the secretor status, the short- and the long-chain Lex antigens can be detected in mature and immature glandular mucous cells of normal gastric mucosa, respectively; both antigens are also expressed in fetal and carcinoma tissues. In the colon, the type 2 chain and its alpha 2----6 sialylated counterpart are expressed in an oncodevelopmental manner. The short- and the long-chain Lex antigens are significantly enhanced in colonic carcinoma. The glycoproteins with NeuAc alpha 2----6GalNAc residues appear in gastric and colonic carcinoma as well as intestinalized gastric mucosa and transitional mucosa. Thus, some of these antigens were distinctively expressed in certain epithelial cells lining the normal gastrointestinal tract depending on maturation and patients' secretor status, and some were oncodevelopmental or carcinoma-associated antigens of the human gastrointestinal tract.

Histochemical and cytochemical localization of blood group antigens

The oligosaccharide structures of blood group antigens are not the primary gene products; they are constructed in a stepwise manner by adding particular sugar to precursor oligosaccharides via several glycosyltransferases coded for by different blood group genes (Watkins 1966, 1978, 1980). Consequently, final profiles of antigens expressed in each cell type are influenced by many different factors such as the intrinsic composition of glycosyltransferase species which are defined by the genotype of the individuals, relative activity or amount of these enzymes (repression, derepression or induction of the enzymes), competition between enzymes with overlapping substrate specificity, the organization of the enzymes in membranes, utilizability of precursors and specific substrate sugars, and the activity level of degradating enzymes. Changes in the antigen profiles during maturation, differentiation and malignant transformation are thought to be intimately related to the variability of these factors. Although great importance attaches to histo- and cytochemical information on the distribution and levels of glycosyltransferases and messenger RNA corresponding to the relevant enzyme, detailed and precise localization of the blood group antigens and their variants is the base line for analyzing these complex factors. On the basis of individual genotype and histochemical findings about the antigen distribution and the interrelationship between cells and cellular components producing different antigenic structures (cellular and subcellular mosaicism), we can deduce precursor oligosaccharide levels as well as the status of gene activation and its primary product, glycosyltransferases. Thus, these findings are a prerequisite for further analysis at the molecular genetic level. As emphasized in this article, lectin staining or immunostaining methods with MAbs combined with glycosidase digestion procedures are powerful tools for in situ analysis of carbohydrate structures in histochemical systems. Although in some cases valuable results have been obtained by applying the technique, our knowledge concerning the distribution of complex carbohydrate structures is still far from satisfactory. Along with well defined MAbs and lectins, the key to developing our methods further is successful introduction of glycosidases, in particular, endoglycosidases since these reagents are indispensable for analyzing the inner core structures and glycoconjugate species of the blood group antigens. Application of these techniques at the ultrastructural level is an alluring possibility, even though many difficulties must be overcome. Although their functional roles have not yet been determined, a diverse array of macromolecules is known to be decorated with blood group-related antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood group antigen synthesis and degradation in normal and cancerous colonic tissues

ABH antigens are expressed by colonic epithelial cells throughout the colon during fetal life but only in proximal segments during adulthood. Malignant and premalignant colonic tumors frequently exhibit ABH reappearance (distal lesions) or ABH deletion (proximal lesions) and occasionally express incompatible A or B substances. Mechanisms governing these developmental and cancer-associated alterations are unknown. Therefore, experiments were performed to assess the activities of biosynthetic (glycosyltransferase) and degradative (glycosidase) enzymes in normal and cancerous tissues of the proximal and distal colon. In normal colonic mucosa, A, B, and H transferase activities were similar in proximal and distal segments. Analysis of enzyme substrate affinities and product characterization confirmed that the ABH transferases in colonic tissues were similar to the gene-specified transferases in human serum. Glycosidase enzyme activities were also comparable in proximal and distal normal colon. Cancers had lower A and B transferase but similar H transferase activities compared with paired normal mucosa. Thus, the absence of ABH antigen expression in normal distal colon is not caused by insufficient glycosyltransferase activity or excessive glycosidase activity.

Griffonia simplicifolia agglutinin-2-binding glycoprotein as a novel carbohydrate antigen of human colonic carcinoma

Griffonia simplicifolia agglutinin-2-binding glycoprotein (GBG) in human colonic carcinoma was examined immunochemically and histochemically, GBG was extracted from colonic carcinoma as a serum-type glycoprotein of 160 kilodaltons. GBG was not identical with carcinoembryonic antigen (CEA), since its molecular weight and localization in tissue sections were different from those of CEA. The non-reducing terminals of GBG probably carry N-acetylglucosamine, but not blood group determinants. Furthermore, GBG was released by phosphatidylinositol-specific phospholipase C from cell membrane. GBG was suggested to be anchored to the membrane via linkage to a glycosyl-phosphatidylinositol molecule. Among colonic carcinoma-associated antigens, serum-type glycoproteins having N-acetylglucosamine at non-reducing terminals have not previously been reported. GBG is a novel carbohydrate antigen of human colonic carcinoma.

Binding of the blood group-reactive lectins to human adult kidney specimens

The binding of a panel of blood group-reactive lectins to frozen sections of human kidney was studied with a special emphasis on reactivity with endothelia and basement membranes. The blood group A-reactive lectins, all specific for alpha-D-N-acetylgalactosamine (GalNAc), Helix aspersa (HAA), Helix pomatia (HPA), and Griffonia simplicifolia I-A4 (GSA-I-A4) agglutinins bound to the endothelium in specimens with blood groups A and AB. In other samples, these lectins reacted predominantly with tubular basement membranes, as well as with certain tubules. Both Dolichos biflorus (DBA) and Vicia villosa agglutinins (VVA), reported to react with blood group A1 substance, failed to reveal endothelia in most specimens, but bound differently to tubules in all blood groups. The blood group B-reactive lectins, specific for alpha-D-galactose (alpha-Gal) or GalNAc, respectively, GSA-I-B4 and Sophora japonica agglutinin (SJA), bound to the endothelia in specimens from blood group B or AB and in other specimens bound only to certain tubules. Among the blood group O-reactive lectins, specific for alpha-L-fucose (Fuc), Ulex europaeus I agglutinin (UEA-I) conjugates, but not other lectins with a similar nominal specificity, bound strongly to endothelia in specimens with blood group O. The UEA-I conjugates bound distinctly more faintly to endothelia in specimens of other blood groups. The present results indicate that lectins, binding to defined blood group determinants, react with endothelia in specimens of the respective blood group status. Furthermore, they suggest that basement membranes and some tubules in the human kidney show a distinct heterogeneity in their expression of saccharide residues, related to their blood group status.

Changes of glycoconjugates in human hepatocellular carcinoma

Receptors of 12 lectins in 25 cases of human hepatocellular carcinomas (HCC) were histochemically investigated by avidin-biotin-peroxidase complex (ABC) method. Liver tissues of five cirrhotic patients and five normal subjects were used as controls. SJA receptor was absent both in HCC and controls, while LCA and PSA receptors were present in all tissues studied here. Receptors of DBA, PHA, PNA, UEAI and SBA which did not bind to normal, cirrhotic and pericarcinomatous liver tissues had the positive rates of 4%, 44%, 16%, 4% and 12% in HCC, respectively. Four lectins which strongly bound to the non-cancer liver tissues had their receptors in 96% (ConA, WGA, RCAI) and 36% (BSAI) of HCC. The pretreatment of tissue sections with neuraminidase abolished most of WGA receptors and exposed some PNA binding sites. There were many differences in lectin distribution between HCC and noncancer liver tissues. The changes of glycoconjugates in HCC were discussed.

Histochemical demonstration of O-glycosidically linked, type 3 based ABH antigens in human pancreas using lectin staining and glycosidase digestion procedures

Histochemical analyses of the chemical structures of sugar sequences with or without blood group specificity were carried out by combined stepwise digestion of tissue sections with exo- and endoglycosidases and subsequent lectin stainings in formalin-fixed, paraffin-embedded human pancreas. In acinar cells from blood group A or AB secretor individuals, sequential digestion with alpha-N-acetylgalactosaminidase and alpha-L-fucosidase imparted reactivity with peanut agglutinin (PNA) in cells reactive with Dolichos biflorus agglutinin as well as those with Ulex europaeus agglutinin I(UEA-I). Simple fucosidase digestion imparted the PNA reactivity only in UEA-I reactive cells. Sequential digestion with alpha-galactosidase and fucosidase likewise liberated the PNA binding sites in Griffonia simplicifolia agglutinin I-B4 reactive cells from blood group B and AB secretors. Sialidase digestion liberated the PNA binding sites not only in acinar cells but also intercalated duct cells, islet cells of Langerhans and endothelial cells. The PNA reactivity obtained by these enzyme digestions was eliminted by endo-alpha-N-acetylgalactosaminidase (endo-GalNAcdase) digestion. Preexisting PNA affinity in acinar cells from non-secretors was also susceptible to endo-GalNAcdase treatment. Following the endo-GalNAcdase digestion, fucosidase or sialidase digestion recovered the PNA reactivity in acinar cells from nonsecretors. These results show that ABH determinants carried on O-glycosidically linked type 3 chain (D-galactose-(beta 1-3)-N-acetyl-D-galactosamine alpha 1-serine or threonine) are secreted in pancreatic acinar cells and suggest that product coded by the secretor gene is required for the complete conversion of type 3 precursor chains into H determinants.

Histochemical comparison of specificity of three bowel carcinoma-reactive lectins, Griffonia simplicifolia agglutinin-II, peanut agglutinin and Ulex europaeus agglutinin-I

A comparison of the histochemical affinities of three lectins reputedly specific to human large bowel carcinoma, namely Griffonia simplicifolia agglutinin-II (GSA-II), peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I), was done using 28 specimens in which normal mucosa, adenoma and carcinoma tissue were present and in contact with each other. In the normal mucosa, GSA-II and PNA revealed only weak affinity to the Golgi region of epithelial cells, whereas UEA-I showed binding to the apical surface of columnar cells and goblet cell mucins, especially in the right colon. Adenoma was characterized by relatively intense reactivity of the Golgi regions of epithelial cells for GSA-II and PNA as well as reactivity of the apical surface of the columnar cells for UEA-I. In carcinomas the apical surface of columnar cell-type tumor cells was stained most intensely with UEA-I, and then in descending order with GSA-II and PNA. GSA-II- and PNA-reactive carcinoma cells occurred more frequently in invasive carcinoma than in intramucosal carcinoma. Goblet cell-type tumor cells retained the properties of their normal counterparts. Staining with these lectins, especially GSA-II-horseradish peroxidase, might be helpful in the identification of carcinoma cells and for analysis of carcinoma-associated antigens.