The ABO, Lewis and related blood group antigens; a review of structure and biosynthesis

Numerous studies have shown that the antigenic determinants of the ABO blood group system are closely related in biochemical terms to the antigenic determinants of the Hh, P, Lewis and Ii blood group systems. The blood group antigens of each of these systems are formed by the addition of specific sugars to an oligosaccharide precursor chain which may be bound through sphingosine to fatty acids (glycolipid) or through serine or threonine to a peptide chain (glycoproteins). The direct gene products of each of these blood group systems are the glycosyltransferase enzymes which catalyse the addition of the specific sugar thus conferring the specified blood group activity to the glycolipid or glycoprotein molecule. The antigenic determinants of the ABO and Lewis systems in addition to red cells also exist in the body secretions in soluble form when the relevant genes are expressed in the phenotype. The antigens expressed on both the red cells and in the secretions are determined by the interaction of Hh, Sese, ABO and Lele genes.     

Sequence of action of genes at the secretor, H, ABO and Lewis loci.

It is argued that Lewis genes are responsible for adding specificity to glycoprotein molecules after the activities of the secretor, H and ABO genes, respectively, have been expressed. This conclusion is based on the results of studies on the expression of ABO and Lewis antigens in salivas from Australian aborigines, and on biochemical results. A simple figure illustrating the antigens determined on red cells and in body secretions as a result of the action of these genes, in their correct order--secretor, H, ABO, Lewis--is presented.     

Advances in ABO gene expression regulation

The ABO blood group system is vital to blood transfusion and organ transplantation. ABO antigens are the most important of all blood group antigens in clinical practice, and are not only present in red blood cells and platelets, but also in most secretions and epithelial tissues. ABO antigens are known to undergo drastic changes during the development, differentiation, and maturation of normal cells. Profound changes have also been documented in pathological processes such as tumorigenesis. To elucidate the molecular basis of how ABO genes are controlled in cell type specific expressions, such as normal cell differentiation or in cancer cells lacking A/B antigens, it is essential to understand the regulatory mechanisms of ABO gene expression. In this review, current knowledge concerning the regulatory mechanisms of ABO gene expression was summarized.     

Regulation of expression of carbohydrate blood group antigens

The carbohydrate antigens associated with the human ABO and Lewis blood group systems are excellent models for the study of the genetic regulation of glycoconjugate biosynthesis because their expression on erythrocytes and in saliva has been thoroughly investigated in terms of classical genetics and the chemical structures and pathways for the formation of the antigens are now well understood. The primary protein products of the blood group genes are believed to be the glycosyltransferase enzymes that complete the biosynthesis of the determinants. The important controlling factors still to be elucidated are the genetic and environmental influences leading to the tissue specific expression of these antigens. The 3 types of regulation mechanisms discussed in this review are those arising: 1) from the specificity requirements of the glycosyltransferases encoded by the blood group genes; 2) from the competition or co-operation of glycosyltransferases encoded by genes at the same or independent loci; and 3) from the existence and tissue distribution of glycosyltransferases with related, but not identical, substrate specificities.     

Glycosphingolipids of human large intestine: detailed structural characterization with special reference to blood group compounds and bacterial receptor structures

Non-acid glycosphingolipid expression was studied in the large intestines from four individuals with the A1Le(a-b+), BLe(a-b+), and OLe(a-b+) blood group phenotypes. In the A1Le(a-b+) case, specimens were taken from the ascending and sigmoid parts of the large intestine in order to compare the expression of glycolipids in the proximal and distal regions of the intestine. In one blood group OLe(a-b+) individual, epithelial cells were isolated from the residual stroma to compare the glycolipid compositions in these two tissue compartments. GlcCer, GalCer, LacCer, Gb3Cer, and Gb4Cer were the major compounds in all three individuals, as shown by mass spectrometry, proton NMR spectroscopy, and degradation studies. The Lea-5 glycolipid was the major complex blood group glycolipid in all individuals, except in the proximal ascending part of the large intestine of the A1Le(a-b+) case, in which the Leb-6 glycolipid was predominant. There were trace amounts of blood group ABH glycolipids, in agreement with the ABO blood group phenotypes of the donors, Lewis antigens with more than six sugar residues in the carbohydrate chain, and blood group X and Y glycolipid antigens. The epithelial cells were dominated by monoglycosylceramides and the Lea-5 glycolipid, while only trace amounts of di-, tri-, and tetraglycosylceramide structures were present. No reactivity was seen in the epithelial cell fraction with Gal alpha 1-4Gal specific Escherichia coli, anti-Pk, or anti-P antibodies, indicating the absence of the glycolipid-borne Gal alpha 1-4Gal sequence in human large intestinal epithelial cells.     

The distribution of type-2 chain histo-blood group antigens in normal cycling human endometrium

Summary The blood group ABO(H) determinants are major allogenic antigens in both erythrocytes and tissue of man. These antigens and related carbohydrates are markers of cellular maturation and differentiation in many epithelial tissues and have recently attracted great interest as tumor-associated antigens. Previous studies of endometrial tissues have indicated that glycosylation in this tissue may be related to hormonal stimulation. We have investigated the immunohistochemical distribution of type-2 chain histo-blood group-related carbohydrates in specimens of normal, cycling endometria obtained from hysterectomies on women with known ABO/Lewis erythrocyte type and saliva secretor status. N-acetyllactosamine and Le^x were demonstrated to be uninfluenced by the genetic background. A and Ale^y antigens were exclusively demonstrated in endometria from blood group A individuals, while Le^y was expressed in endometria from blood group 0 individuals mainly. The precursor N-acetyllactosamine as well as the terminal H, A, and ALe^y antigens were shown in only a few cells. In contrast, N-acetyllactosamine substituted by sialic acid and/or fucose residues (Le^x, sialosyl-Le^x, Le^y) were demonstrated in epithelial cells of normal, cycling endometrium, but with both quantitative and qualitative differences in staining relating to the menstrual cycle, indicating that type-2 chain antigens are expressed under both genetic and hormonal influence in human cycling endometrium.     

Antigenic and functional properties of the human red blood cell urea transporter hUT-B1

The Kidd (JK) blood group locus encodes the urea transporter hUT-B1, which is expressed on human red blood cells and other tissues. The common JK*A/JK*B blood group polymorphism is caused by a single nucleotide transition G838A changing Asp-280 to Asn-280 on the polypeptide, and transfection of erythroleukemic K562 cells with hUT-B1 cDNAs carrying either the G838 or the A838 nucleotide substitutions resulted in the isolation of stable clones that expressed the Jk(a) or Jk(b) antigens, respectively, thus providing the first direct demonstration that the hUT-B1 gene encodes the Kidd blood group antigens. In addition, immunochemical analysis of red blood cells demonstrated that hUT-B1 also exhibits ABO determinants attached to the single N-linked sugar chain at Asn-211. Moreover, immunoadsorption studies, using inside-out and right-side-out red cell membrane vesicles as competing antigen, demonstrated that the C- and N-terminal ends of hUT-B1 are oriented intracellularly. Mutagenesis and functional studies by expression in Xenopus oocytes revealed that both cysteines Cys-25 and Cys-30 (but not alone) are essential for plasma membrane addressing. Conversely, the transport function was not affected by the JK*A/JK*B polymorphism, C-terminal deletion (residues 360-389), or mutation of the extracellular N-glycosylation consensus site and remains poorly para-chloromercuribenzene sulfonate (pCMBS)-sensitive. However, transport studies by stopped flow light scattering using Jk-K562 transfectants demonstrated that the hUT-B1-mediated urea transport is pCMBS-sensitive in an erythroid context, as reported previously for the transporter of human red blood cells. Mutagenesis analysis also indicated that Cys-151 and Cys-236, at least alone, are not involved in pCMBS inhibition. Altogether, these antigenic, topologic, and functional properties might have implications into the physiology of hUT-B1 and other members of the urea transporter family.     

Role of ABO secretor status in mucosal innate immunity and H. pylori infection

The fucosylated ABH antigens, which constitute the molecular basis for the ABO blood group system, are also expressed in salivary secretions and gastrointestinal epithelia in individuals of positive secretor status; however, the biological function of the ABO blood group system is unknown. Gastric mucosa biopsies of 41 Rhesus monkeys originating from Southern Asia were analyzed by immunohistochemistry. A majority of these animals were found to be of blood group B and weak-secretor phenotype (i.e., expressing both Lewis a and Lewis b antigens), which are also common in South Asian human populations. A selected group of ten monkeys was inoculated with Helicobacter pylori and studied for changes in gastric mucosal glycosylation during a 10-month period. We observed a loss in mucosal fucosylation and concurrent induction and time-dependent dynamics in gastric mucosal sialylation (carbohydrate marker of inflammation), which affect H. pylori adhesion targets and thus modulate host-bacterial interactions. Of particular relevance, gastric mucosal density of H. pylori, gastritis, and sialylation were all higher in secretor individuals compared to weak-secretors, the latter being apparently "protected." These results demonstrate that the secretor status plays an intrinsic role in resistance to H. pylori infection and suggest that the fucosylated secretor ABH antigens constitute interactive members of the human and primate mucosal innate immune system.     

Norwalk virus-like particles bind specifically to A,H and difucosylated Lewis but not to B histo-blood group active glycosphingolipids

Noroviruses and norovirus virus-like particles (VLPs) exhibit strain specific patterns in their binding to ABH and Lewis histo-blood group antigens. In this study we demonstrate for the first time specific binding of Norwalk virus VLPs to type 1 and type 2 chain glycosphingolipids (GSLs) carrying ABH and Lewis antigens. N-succinimidyl-3-tributylstannyl benzoate (ATE) was precursor labeled with ¹²⁵I and then conjugated to VLPs. The ¹²⁵I-VLPs were used in GSL thin-layer chromatogram binding assays and displayed binding to H type 1, Lewis b, A type 1, A Lewis b GSLs but no binding to B type 1 or B Lewis b GSLs. For the type 2 chain GSLs the Norwalk VLPs bound to H type 2, Lewis y, A type 2 and A Lewis y. In addition, the VLPs bound to several complex GSLs from blood group O and A, but not from blood group B red blood cells.     

Expression of Lewis antigenic determinants in colorectal adenocarcinomas

Expression of type 1 and type 2 chain Lewis antigens was studied in 32 rectal adenocarcinoma specimens; the results were correlated with the patients' Lewis phenotype and secretor status. In addition, the pattern of expression of these antigens was analyzed in adjacent and distant normal mucosa. We used an indirect immunofluorescence technique with p-phenylenediamine counterstaining (Oriol technique) and a panel of monoclonal antibodies directed against the different antigenic specificities. Normal distal colonic mucosa only expresses monofucosylated structures (Lea and X) arising from activity of the alpha 1-3,4-fucosyltransferase coded by the Le gene. Rectal adenocarcinomas also show Lea and X, but also reexpress blood group antigens ABH and exhibit difucosylated determinants (Leb and Y). The accumulation of mono- and difucosylated type 2 chain in neoplastic processes, independently of the Le and Se genes, could be due to the enzymes coded by reactivation of the H and X genes. Blood group antigens form a complex signal code, genetically regulated, which intervenes in differentiation, growth and cellular recognition processes, and which may undergo important modifications during malignant transformation. These alterations could be useful in the diagnosis and prognosis of some types of carcinoma.     

Blood group A glycolipid antigen expression in kidney, ureter, kidney artery, and kidney vein from a blood group A1Le(a-b+) human individual. Evidence for a novel blood group A heptaglycosylceramide based on a type 3 carbohydrate chain

Kidney, ureter, kidney artery, and kidney vein tissue were obtained from a single human transplant specimen. The donors erythrocyte blood group phenotype was A1Le(a-b+). Total non-acid glycolipid fractions were isolated and individual glycolipid components were identified by immunostaining thin layer plates with a panel of monoclonal antibodies and by mass spectrometry of the permethylated and permethylated-reduced total glycolipid fractions. The dominating glycolipids in all tissues were mono- to tetraglycosylceramides. In the kidney, ureter, and artery tissue less than 1% of the glycolipids were of blood group type, having more than 4 sugar residues. In contrast, 14% of the vein glycolipids were of blood group type, and the dominating components were type 1 chain blood group H pentaglycosylceramides and A hexaglycosylceramides. Trace amounts of structurally different blood group A glycolipids (type 1 to 4 core saccharide chains) with up to 10 sugar residues were found in the kidney, ureter, and vein tissues, including evidence for a novel blood group A heptaglycosylceramide based on the type 3 chain in the vein. The only detected A glycolipid antigen in the artery tissue was the blood group A difucosyl type 1 chain heptaglycosylceramide (ALeb) structure. Blood group Lewis and related antigens (Lea, Leb, and ALeb) were expressed in the kidney, ureter, and artery, but were completely lacking in the vein, indicating that the Le gene-coded alpha 1-4-fucosyltransferase was not expressed in this tissue. The X and Y antigens (type 2 chain isomers of the Lea and Leb antigens) were detected only in the kidney tissue.     

Possible role of ABO system in age-related diseases and longevity: a narrative review

ABO blood group antigens are expressed either on the surface of red blood cells either on a variety of other cells. Based on the available knowledge of the genes involved in their biosynthesis and their tissue distribution, their polymorphism has been suggested to provide intraspecies diversity allowing to cope with diverse and rapidly evolving pathogens. Accordingly, the different prevalence of ABO group genotypes among the populations has been demonstrated to be driven by malaria selection. In the similar manner, a particular ABO blood group may contribute to favour life-extension via biological mechanisms important for surviving or eluding serious disease. In this review, we will suggest the possible association of ABO group with age-related diseases and longevity taking into account the biological role of the ABO glycosyltransferases on some inflammatory mediators as adhesion molecules.     

The partial characterisation of maternal anti-trophoblast antibody responses generated during normal human pregnancy

The anti-trophoblast antibody response generated during a normal human pregnancy and detected by a recently developed enzyme-linked immunosorbent assay, was partially characterised in terms of maternal influences, nature of the antibodies and nature of the antigenic determinants present on the syncytiotrophoblast plasma membrane. The level and incidence of the response was significantly affected by maternal parity, while the maternal ABO, but not Rhesus, blood group antigens exerted a minor influence. The antibody response was predominantly mediated by IgG molecules of the IgG1,2 and 4 subclasses. The IgG molecules existed in the maternal sera either in the form of 'free' molecules or were involved in immune complexes. The antibodies interacted with determinants that were present on all the placental membranes tested and hence are possibly organ specific. The antigenic specificities were absent from erythrocytes and peripheral blood lymphocytes.     

The blood group B type-4 heptaglycosylceramide is a minor blood group B structure in human B kidneys in contrast to the corresponding A type-4 compound in A kidneys. Structural and in vitro biosynthetic studies.

Blood group A glycolipid antigens have been found based upon at least four different core saccharides (types 1 to 4). The biological significance of this structural polymorphism is not known, although the successful outcome of transplantations of blood group A2 kidneys to blood group O individuals have been partly explained by the low expression of A type-3 and -4 chain glycolipid antigens in A2 kidneys. If graft rejection due to ABO incompatibility is, in any way, correlated to the expression of type-3 and -4 chain blood group glycolipids, it is of interest to identify possible blood group B structures based on these core saccharides. In a non-acid glycosphingolipid fraction isolated from human blood group B kidneys, mass spectrometry, high-temperature gas chromatography-mass spectrometry and probing of thin-layer chromatograms with Gal alpha 1-4Gal-specific Escherichia coli and monoclonal anti-B antibodies provided evidence for minute amounts of a Gal alpha 1-3(Fuc alpha 1-2)Gal beta-HexNAc-Gal alpha 1-4Gal beta-Hex-Ceramide structure consistent with a B type-4 chain heptaglycosylceramide. In contrast, blood group A kidneys have the corresponding A type-4 chain heptaglycosylceramide as the predominant blood group A glycolipid. No, or very low activity of the blood group B gene enzyme on the type-4 chain blood group H hexaglycosylceramide precursor was found by biosynthetic experiments in vitro, which might explain the low expression of type-4 chain blood group B heptaglycosylceramides in human blood group B kidneys.     

The blood group B type-4 heptaglycosylceramide is a minor blood group B structure in human B kidneys in contrast to the corresponding A type-4 compound in A kidneys. Structural and in vitro biosynthetic studies

Blood group A glycolipid antigens have been found based upon at least four different core saccharides (types 1 to 4). The biological significance of this structural polymorphism is not known, although the successful outcome of transplantations of blood group A₂ kidneys to blood group O individuals have been partly explained by the low expression of A type-3 and -4 chain glycolipid antigens in A₂ kidneys. If graft rejection due to ABO incompatibility is, in any way, correlated to the expression of type-3 and -4 chain blood group glycolipids, it is of interest to identify possible blood group B structures based on these core saccharides. In a non-acid glycosphingolipid fraction isolated from human blood group B kidneys, mass spectrometry, high-temperature gas chromatography-mass spectrometry and probing of thin-layer chromatograms with Galα1–4Gal-specific Escherichia coli and monoclonal anti-B antibodies provided evidence for minute amounts of Gaα1–3(Fucα1–2)Galβ-HexNac-Galα1–4Galβ-Hex-Ceramide structure consistent with a B type-4 chain heptaglycosylceramide. In contrast, blood group A kidneys have the corresponding A type-4 chain heptaglycosylceramide as the predominant glood group A glycolipid. No, or very low activity of the blood group B gene enzyme on the type-4 chain blood group H hexaglycosylceramide precursor was found by biosynthetic experiments in vitro, which migh explain the low expression of type-4 chain blood group heptaglycosylceramides in human blood group B kidneys.     

The specific glycosphingolipid composition of human ureteral epithelial cells

Total non-acid and acid glycolipid fractions were isolated from epithelial cell scrapings and the non-epithelial residue of a human upper ureter. The glycolipid fractions were structurally characterized as total mixtures by thin-layer chromatography, mass spectrometry, and proton NMR spectroscopy. Selected structural information was also obtained on binding of monoclonal antibodies and bacteria to the thin-layer chromatograms. The major epithelial cell glycolipids were Glc beta 1-1ceramide (75%), dihexosylceramide (10%) and NeuAcLacceramide (10%). In addition, 8 minor glycolipids belonging to the blood group P, Lewis and ABO systems were identified. The major glycolipids of the non-epithelial residues were mono- and dihexosylceramides together with globotriaosyl- and globotetraosylceramides. The epithelial mono- and diglycosylceramide compounds had an unusual ceramide composition with mainly C18 and C20 trihydroxy long chain bases in combination with C22-C24 hydroxy fatty acids in contrast to the non-epithelial glycolipids which contained mainly C18 dihydroxy long chain bases in combination with C16-C24 non-hydroxy fatty acids.     

Association of the ABO blood group with certain human diseases

Following the discovery of ABO blood group over 100 years ago, a variety of studies sought to determine whether different disease states are influenced by ABO inheritance. As oligosaccharide antigens, ABO blood group antigens are widely expressed on the membrane of red blood cells and tissue cells, as well as in the saliva and body fluid. It is by far the most important blood group system in human immunohematology and transfusion medicine. While, other than determining blood group phenotype, accumulating evidence indicates that ABO blood group is implicated in the development of a number of human diseases. This review mainly focuses on the association between ABO blood group and cardiovascular system risk, corona virus disease 2019 (COVID-19), affective disorders, allergic diseases, as well as cancers.     

Individuals with Le(a+b-) blood group have increased susceptibility to symptomatic vibrio cholerae O1 infection

Background

Human genetic factors such as blood group antigens may affect the severity of infectious diseases. Presence of specific ABO and Lewis blood group antigens has been shown previously to be associated with the risk of different enteric infections. The aim of this study was to determine the relationship of the Lewis blood group antigens with susceptibility to cholera, as well as severity of disease and immune responses to infection.

Methodology

We determined Lewis and ABO blood groups of a cohort of patients infected by Vibrio cholerae O1, their household contacts, and healthy controls, and analyzed the risk of symptomatic infection, severity of disease if infected and immune response following infection.

Principal Findings

We found that more individuals with cholera expressed the Le(a+b−) phenotype than the asymptomatic household contacts (OR 1.91, 95% CI 1.03–3.56) or healthy controls (OR 1.90, 95% CI 1.13–3.21), as has been seen previously for the risk of symptomatic ETEC infection. Le(a–b+) individuals were less susceptible to cholera and if infected, required less intravenous fluid replacement in hospital, suggesting that this blood group may be associated with protection against V. cholerae O1. Individuals with Le(a–b−) blood group phenotype who had symptomatic cholera had a longer duration of diarrhea and required higher volumes of intravenous fluid replacement. In addition, individuals with Le(a–b−) phenotype also had lessened plasma IgA responses to V. cholerae O1 lipopolysaccharide on day 7 after infection compared to individuals in the other two Lewis blood group phenotypes.

Conclusion

Individuals with Lewis blood type Le(a+b−) are more susceptible and Le(a–b+) are less susceptible to V. cholerae O1 associated symptomatic disease. Presence of this histo-blood group antigen may be included in evaluating the risk for cholera in a population, as well as in vaccine efficacy studies, as is currently being done for the ABO blood group antigens.     

The molecular genetics of blood group polymorphism

Over 300 blood group specificities on red cells have been identified, many of which are polymorphic. The molecular mechanisms responsible for these polymorphisms are diverse, though many simply represent single nucleotide polymorphisms (SNPs). Other mechanisms include the following: gene deletion; single nucleotide deletion and sequence duplication, which introduce reading-frame shifts; nonsense mutation; intergenic recombination between closely linked genes, giving rise to hybrid genes and hybrid proteins; and a SNP in the promoter region of a blood group gene. Examples of these various genetic mechanisms are taken from the ABO, Rh, Kell, and Duffy blood group systems. Null phenotypes, in which no antigens of a blood group system are expressed, are not generally polymorphic, but provide good examples of the effect of inactivating mutations on blood group expression. As natural human ‘knock-outs’, null phenotypes provide useful clues to the functions of blood group antigens. Knowledge of the molecular backgrounds of blood group polymorphisms provides a means to predict blood group phenotypes from genomic DNA. This has two main applications in transfusion medicine: determination of foetal blood groups to assess whether the foetus is at risk from haemolytic disease and ascertainment of blood group phenotypes in multiply transfused, transfusion-dependent patients, where serological tests are precluded by the presence of donor red cells. Other applications are being developed for the future.