Blood group-active surface molecules of the human red blood cell

Human Cell-Camouflaged Nanomagnetic Scavengers Restore Immune Homeostasis in a Rodent Model with Bacteremia

Bloodstream infection caused by antimicrobial resistance pathogens is a global concern because it is difficult to treat with conventional therapy. Here, scavenger magnetic nanoparticles enveloped by nanovesicles derived from blood cells (MNVs) are reported, which magnetically eradicate an extreme range of pathogens in an extracorporeal circuit. It is quantitatively revealed that glycophorin A and complement receptor (CR) 1 on red blood cell (RBC)-MNVs predominantly capture human fecal bacteria, carbapenem-resistant (CR) Escherichia  coli, and extended-spectrum beta-lactamases-positive (ESBL-positive) E. coli, vancomycin-intermediate Staphylococcus aureus (VISA), endotoxins, and proinflammatory cytokines in human blood. Additionally, CR3 and CR1 on white blood cell-MNVs mainly contribute to depleting the virus envelope proteins of Zika, SARS-CoV-2, and their variants in human blood. Supplementing opsonins into the blood significantly augments the pathogen removal efficiency due to its combinatorial interactions between pathogens and CR1 and CR3 on MNVs. The extracorporeal blood cleansing enables full recovery of lethally infected rodent animals within 7 days by treating them twice in series. It is also validated that parameters reflecting immune homeostasis, such as blood cell counts, cytokine levels, and transcriptomics changes, are restored in blood of the fatally infected rats after treatment.

Loci and motifs of the GalNAcα1 → 3/O related glycotopes in the mammalian glycoconjugates and their lectin recognition roles

Galα1 → and GalNAcα1 → are the two essential key sugars in human blood group AB active glycotopes, in which GalNAcα1 → related sequences are located at both sides of the nonreducing and the reducing ends of human blood group A active O-glycans. It is also found at the nonreducing ends of GlcNAc N-glycans and glycosphingolipid(GSL) of human blood group A active glycotopes (A_h) and Forssman antigen (F_p). When monosaccharides and their α, β anomers are involved in basic units to express the complex size of the combining sites of the GalNAcα1 → specific lectins, they can be divided into a cavity site to accommodate the GalNAcα → key sugar and a subsite with a wide and broad range of recognition area to adopt the rest part of sugar sequences or glycotopes. The function of the subsite is assumed to act as an enhancement factor to increase its affinity power. The following three points are the theme of this mini review: (1) the loci and distribution of the GalNAcα1 → related glycotopes in mammalian glycoconjugates are illustrated and their chemical structures are advanced by the expression of the disaccharide units and code system; (2) the sizes and motifs of GalNAcα1 → specific lectin-glycan interactions are given and (3) the role of the polyvalent blood group A_h and B_h glycotopes as blood group AB antigens are proposed. These three highlights should provide an essential background required for the advances in this field.

Identification of erythrocyte membrane proteins interacting with Mycoplasma suis GAPDH and OSGEP

Mycoplasma suis (M. suis) is an uncultivable haemotrophic mycoplasma that parasitizes the red blood cells of a wide range of domestic and wild animals. Adhesion of M. suis to host erythrocytes is crucial for its unique RBC-dependent lifecycle. MSG1 protein (now named as GAPDH) with homology to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was the first identified adhesion protein of M. suis. In this study, we found that O-sialoglycoprotein endopeptidase (OSGEP) is another M. suis protein capable of binding porcine erythrocytes. Recombinant OSGEP expressed in E. coli demonstrated surface localization similar to GAPDH. Purified rOSGEP bound to erythrocyte membrane preparations in a dose-dependent manner and this adhesion could be specifically inhibited by anti-rOSGEP antibodies. E. coli transformants expressing OSGEP on their surface were able to adhere to porcine erythrocytes. Furthermore, using far-western and pull-down assays, we determined the host membrane proteins that interacted with OSGEP and GAPDH were Band3 and glycophorin A (GPA). In conclusion, our studies indicated that OSGEP and GAPDH could interact with both Band3 and GPA to mediate adhesion of M. suis to porcine erythrocytes.

Differential recognition of natural and remodeled glycotopes by three Diocleae lectins

The carbohydrate specificities of Dioclea grandiflora lectins DGL-I¹ and DGL-II, and Galactia lindenii lectin II (GLL-II) were explored by use of remodeled glycoproteins as well as by the lectin hemagglutinating activity against erythrocytes from various species with different glycomic profiles. The three lectins exhibited differences in glycan binding specificity but also showed overlapping recognition of some glycotopes (i.e. Tα glycotope for the three lectins; IIβ glycotope for DGL-II and GLL-II lectins); in many cases the interaction with distinct glycotopes was influenced by the structural context, i.e., by the neighbouring sugar residues. Our data complement and expand the existing knowledge about the binding specificity of these three Diocleae lectins, and taken together with results of previous studies, allow us to suggest a functional map of the carbohydrate recognition which illustrate the impact of modification of basic glycotopes enhancing, permiting, or inhibiting their recognition by each lectin.

A Comprehensive Review of Our Current Understanding of Red Blood Cell (RBC) Glycoproteins

Human red blood cells (RBC), which are the cells most commonly used in the study of biological membranes, have some glycoproteins in their cell membrane. These membrane proteins are band 3 and glycophorins A-D, and some substoichiometric glycoproteins (e.g., CD44, CD47, Lu, Kell, Duffy). The oligosaccharide that band 3 contains has one N-linked oligosaccharide, and glycophorins possess mostly O-linked oligosaccharides. The end of the O-linked oligosaccharide is linked to sialic acid. In humans, this sialic acid is N-acetylneuraminic acid (NeuAc). Another sialic acid, N-glycolylneuraminic acid (NeuGc) is present in red blood cells of non-human origin. While the biological function of band 3 is well known as an anion exchanger, it has been suggested that the oligosaccharide of band 3 does not affect the anion transport function. Although band 3 has been studied in detail, the physiological functions of glycophorins remain unclear. This review mainly describes the sialo-oligosaccharide structures of band 3 and glycophorins, followed by a discussion of the physiological functions that have been reported in the literature to date. Moreover, other glycoproteins in red blood cell membranes of non-human origin are described, and the physiological function of glycophorin in carp red blood cell membranes is discussed with respect to its bacteriostatic activity.

Antigenically shielded universal red blood cells by polydopamine-based cell surface engineering

A strategy of surface engineering by using polydopamine was developed to shelter antigens on red blood cells and prevent coagulation reactions.

Modulation of glycan recognition by clustered saccharide patches

All cells in nature are covered with a dense and complex array of glycan chains. Specific recognition and binding of glycans is a critical aspect of cellular interactions, both within and between species. Glycan-protein interactions tend to be of low affinity but high specificity, typically utilizing multivalency to generate the affinity required for biologically relevant binding. This review focuses on a higher level of glycan organization, the formation of clustered saccharide patches (CSPs), which can constitute unique ligands for highly specific interactions. Due to technical challenges, this aspect of glycan recognition remains poorly understood. We present a wealth of evidence for CSPs-mediated interactions, and discuss recent advances in experimental tools that are beginning to provide new insights into the composition and organization of CSPs. The examples presented here are likely the tip of the iceberg, and much further work is needed to elucidate fully this higher level of glycan organization.

Clinical and molecular research of neuroacanthocytosis

Neuroacanthocytosis is an autosomal recessive or dominant inherited disease characterized by widespread, non-specific nervous system symptoms, or spiculated "acanthocytic" red blood cells. The clinical manifestations typically involve chorea and dystonia, or a range of other movement disorders. Psychiatric and cognitive symptoms may also be present. The two core neuroacanthocytosis syndromes, in which acanthocytosis is atypical, are autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome. Acanthocytes are found in a smaller proportion of patients with Huntington's disease-like 2 and pantothenate kinase-associated neurodegeneration. Because the clinical manifestations are diverse and complicated, in this review we present features of inheritance, age of onset, neuroimaging and laboratory findings, as well as the spectrum of central and peripheral neurological abnormalities and extraneuronal involvement to help distinguish the four specific syndromes.

[Phenotype characteristics of humoral immunity parameters in patients with chronic generalized periodontitis with different blood groups]

Interrelationships between parameters of humoral immunity with AB0 blood groups have been investigated. The highest content of IgA to transglutaminase was found in A(II) patients, while the lowest content was found in AB(IV) patients. The blood content on anti-gliadin IgA was higher in healthy donors. The oral liquid of periodontic patients contained anti-gliadin IgA and IgB lacking in healthy donors. It have been found that 47% of healthy people and 52.7% of patients are infcted with Helicobacter pylori. In the group of periodontic patients A(II) individually predominated; they were characterized by the presence of antibodies to H. pylori in the oral liquid, these antibodies were absent in healthy donors. The pepsinogen level was higher in blood of periodontic patients than in healthy donors. B(III) patients had the lowest level of blood pepsinogen.

Developmental validation of a novel lateral flow strip test for rapid identification of human blood (Rapid Stain Identification--Blood)

Human blood is the body fluid most commonly encountered at crime scenes, and blood detection may aid investigators in reconstructing what occurred during a crime. In addition, blood detection can help determine which items of evidence should be processed for DNA-STR testing. Unfortunately, many common substances can cause red-brown stains that resemble blood. Furthermore, many current human blood detection methods are presumptive and prone to false positive results. Here, the developmental validation of a new blood identification test, Rapid Stain Identification--Blood (RSID--Blood), is described. RSID--Blood utilizes two anti-glycophorin A (red blood cell membrane specific protein) monoclonal antibodies in a lateral flow strip test format to detect human blood. We present evidence demonstrating that this test is accurate, reproducible, easy to use, and highly specific for human blood. Importantly, RSID--Blood does not cross-react with ferret, skunk, or primate blood and exhibits no high-dose hook effect. Also, we describe studies on the sensitivity, body fluid specificity, and species specificity of RSID--Blood. In addition, we show that the test can detect blood from a variety of forensic exhibits prior to processing for DNA-STR analysis. In conclusion, we suggest that RSID--Blood is effective and useful for the detection of human blood on forensic exhibits, and offers improved blood detection when compared to other currently used methods.

Biological gas channels for NH3 and CO2: evidence that Rh (Rhesus) proteins are CO2 channels

Physiological evidence from our laboratory indicates that Amt/Mep proteins are gas channels for NH3, the first biological gas channels to be described. This view has now been confirmed by structural evidence and is displacing the previous belief that Amt/Mep proteins were active transporters for the NH4+ ion. Still disputed is the physiological substrate for Rh proteins, the only known homologues of Amt/Mep proteins. Many think they are mammalian ammonium (NH4+ or NH3) transporters. Following Monod's famous dictum, "Anything found to be true of E. coli must also be true of elephants" [Perspect. Biol. Med. 47(1) (2004) 47], we explored the substrate for Rh proteins in the unicellular green alga Chlamydomonas reinhardtii. C. reinhardtii is one of the simplest organisms to have Rh proteins and it also has Amt proteins. Physiological studies in this microbe indicate that the substrate for Rh proteins is CO2 and confirm that the substrate for Amt proteins is NH3. Both are readily hydrated gases. Knowing that transport of CO2 is the ancestral function of Rh proteins supports the inference from hematological research that a newly evolving role of the human Rh30 proteins, RhCcEe and RhD, is to help maintain the flexible, flattened shape of the red cell.

Genetic polymorphism and TH1/TH2 orientation

BACKGROUND

It is likely that besides developmental and environmental factors, genetic factors also play an important role in Th1/Th2 orientation and susceptibility to related disorders. Thus, for each genetic factor involved one would expect an opposite pattern of susceptibility towards Th1- and Th2-associated diseases.

METHODS

We report a comparative analysis of the pattern of association of four genetic polymorphisms with bronchial asthma (Th2 disease) and Crohn's disease (CD; Th1 disease). The study population included 291 Roman children with bronchial asthma and 72 adult Romans with CD, and haptoglobin, adenosine deaminase (ADA), acid phosphatase locus 1 (ACP1) and MN phenotypes were determined.

RESULTS

Compared with controls from the same population, the pattern of phenotype association observed in bronchial asthma is exactly opposite to that observed in CD. The analysis of pairwise gametic type distribution for ACP1, ADA and MN polymorphisms has shown that the pattern of differences between bronchial asthma and controls is opposite to that observed between CD and controls.

CONCLUSIONS

The pattern of differences between bronchial asthma versus CD is compatible with the hypothesis that some of the genetic systems considered contribute to Th1/Th2 orientation.

Atopic and nonatopic asthma in children

In 155 asthmatic children we have studied the relationship between prick test positivity and a set of genetic factors previously found to be associated with bronchial asthma. Among these factors, MN system (p = 0.009) and age at onset of symptoms (p = 0.05) are the most important variables separating prick test negative from prick test positive children. MN and age at onset influence independently prick test positivity pointing to an additive effect of the two variables. M phenotype appears correlated positively with an increased susceptibility to nonallergic asthma in all age groups, whereas N phenotype appears correlated positively with age at onset but in allergic asthma only. The MN system codifies for glycophorin A, a sialoglycoprotein that represents a major ligand for several bacteria and viruses that recognize the N-acetylneuraminic acid present in this protein. The present data suggest that genetic variability in this system might influence bacterial and viral competition and mucosal damage influencing susceptibility to asthmatic reactions in absence of IgE hyperproduction.

Distinct regions of human glycophorin A enhance human red cell anion exchanger (band 3; AE1) transport function and surface trafficking

Human red cell glycophorin A (GPA) enhances the expression of band 3 anion transport activity at the cell surface of Xenopus oocytes. This effect of GPA could occur in two ways, enhancement of band 3 anion transport function or enhancement of band 3 trafficking to the cell surface. We have examined the GPA effect using GPA mutants. We compared the sequences of GPA and its homolog glycophorin B (GPB; which does not facilitate band 3 cell-surface activity or trafficking) to identify candidate regions of GPA for study. We constructed several GPA or GPB mutants, including naturally occurring GPA/GPB hybrid molecules and insertion, deletion, and substitution mutants. We analyzed the effects of the mutant proteins on band 3-specific chloride transport and surface presentation using co-expression in Xenopus oocytes. We find that the C-terminal cytoplasmic tail of GPA enhances trafficking of band 3 to the cell surface, whereas the extracellular residues 68-70 increase the specific anion transport activity of band 3. In addition, examination of the oligomerization of GPA mutants showed that single amino acid substitutions N-terminal to the transmembrane domain greatly reduce SDS-stable GPA dimer formation, implying that regions outside the transmembrane domain of GPA are important for GPA dimer formation.

Intrauterine development and MNSs blood groups in repeated spontaneous abortion

OBJECTIVES

To determine whether the maternal MNSs genotype has an effect on the birth weight and gestation duration of the live offspring of women with repeated primary spontaneous abortion (RSA).

METHODS

The study sample consisted of 239 healthy white women who had been delivered of a live infant, and 137 women with a history of primary RSA-54 of whom had recently been delivered of a live infant and 83 who had had a spontaneous abortion. Maternal MNSs phenotypes were determined by standard serological methods, and the results were analyzed for relationships between these phenotypes and the mothers' reproductive status and the infants' birth weight and gestational age. Analysis of variance, the chi(2)-test of independence, and the Mantel-Haenszel test for linear association were performed for data analysis.

RESULTS

Infants born to mothers with the Ss genotype showed significantly lower birth weight and gestational duration compared with the infants of mothers with other genotypes. Additionally, the MNSs haplotype was found to be associated with birth weight.

CONCLUSIONS

Previous studies have shown that the MNSs system influences the gestational age of aborted fetuses in cases of RSA. The present study supports the hypothesis that this genetic factor influences intrauterine growth and development in women experiencing RSA.

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.

Characterization of blood group ABO(H)-active gangliosides in type AB erythrocytes and structural analysis of type A-active ganglioside variants in type A human erythrocytes

Several monosialogangliosides containing the type A-active epitope have been detected in type A erythrocytes on immunological analysis with a monoclonal antibody, and three of them were purified by repeated silica bead column chromatography and by scraping from the TLC plate. Two of these A-active gangliosides were characterized by methylation analysis by GC/MS, negative SIMS, MALDI-TOF/MS, proton nuclear magnetic resonance spectroscopy, and immunological assays, and their structures were concluded to be as follows. A-active ganglioside I:A-active ganglioside II:The reactivity of the purified gangliosides to the anti-A monoclonal antibodies (mAbs) exhibited enhancement after removal of the sialic acid. Therefore, the sialic residue has been shown to inhibit the binding to the terminal A-active epitope through the formation of an immune complex. To confirm the presence of A- (including S-A-I, -II and -III) and B-active gangliosides, the reactivity of anti-A and -B mAbs were investigated using total gangliosides from type A, -B and -AB erythrocytes on TLC plate. The results were that the gangliosides from types A and AB showed positive reaction to anti-A mAbs, whereas in the anti-B mAbs binding the gangliosides from types B and AB were positive. Thus, it revealed that A-active gangliosides were present in type A and -AB, and B-active gangliosides in types B and AB. As there was no difference in respective gangliosides on type AB erythrocytes of 22 individuals, both A- and B-active gangliosides are equally present in type AB erythrocytes. The biological significance of these A- and B-active ganglioside variants remains vague at present. As these molecules exhibit different reactivities to the anti-A mAbs, it is very likely that they can regulate the antigenicity of the A-epitope on the cell surface.

Genomic typing of human red cell miltenberger glycophorins in a Taiwanese population

BACKGROUND

Antigens in the human red cell Miltenberger series are glycophorin variants of the MN (MNS) blood group system that are due to the rearrangement of glycophorin A (GPA) and glycophorin B (GPB) genes.

STUDY DESIGN AND METHODS

Taking advantage of the differences between the GPA and GPB genes, a polymerase chain reaction-based method was developed to detect all the Miltenberger glycophorin variants and St(a) subtype. GPA- and GPB-specific primers were used to amplify the GPA or GPB gene, and the amplified products were used to recognize the different hybrid genes after restriction enzyme digestions.

RESULTS

Among 264 Taiwanese subjects studied, Mi.III and St(a) are the most common types of Miltenberger variants found. Mi.III was present in 13 (4.92%) of 264, and St(a) was found in 8 (3. 03%) of 264; 1 case (0.4%) of Mi.V was also identified from the study group.

CONCLUSION

This is the first polymerase chain reaction-based method of detecting most of the Miltenberger variants and St(a). The genomic typing results were confirmed by control DNA of identified Miltenberger phenotypes. The prevalence rates of Mi. III and St(a) in this study were also consistent with other previous reports using different methods.

A single-sample method for determination of carbohydrate and protein contents glycoprotein bands separated by sodium dodecyl sulfate- polyacrylamide gel electrophoresis

A method is described for determination of carbohydrate and protein contents of glycoproteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and then electroblotted onto polyvinylidene difluoride (PVDF) membranes. Blots were stained, and appropriate pieces of PVDF membranes were excised, destained, and subjected to sequential hydrolysis with 0.2 M trifluoroacetic acid (TFA) for 1 h at 80 degrees C, then with 2 M TFA for 4 h at 100 degrees C, and finally with 6 M HCl at 100 degrees C for 24 h to release sialic acids, neutral sugars with hexosamines, and amino acids, respectively. In some instances preliminary methanolysis was used. Carbohydrates including sialic acids were quantitated by high pH anion exchange chromatography with pulsed amperometric detection. Protein content of the bands was determined as amino acids by the fluorescamine or ninhydrin method. In the calculation of results proper adjustments were made for small amounts of fucose released by hydrolysis with 0.2 M TFA at 80 degrees C, and for partial degradation of protein during hydrolysis with 2 M TFA at 100 degrees C. Recoveries of amino acids from hydrolysates of glycoproteins that had been electroblotted onto PVDF membranes equaled those of carbohydrates. This was possible because of preliminary hydrolysis of glycoproteins with TFA, as well as washing of wet, instead of dried, PVDF membranes after hydrolysis with 6 M HCl. The two modifications increased yields of amino acids by about 30%. The method was successfully applied to the determination of molar and weight percentage composition of human transferrin, band 3 protein, glycophorin A, and alpha(1)-acid glycoprotein. In each case the results obtained for directly hydrolyzed and electrophoresed/electroblotted glycoproteins were practically identical. We also determined the glucosamine content of band 4.1 protein of erythrocytes.

A comparison of the Aplysia lectin anti-I specificity with human anti-I and several other I-detecting lectins

BACKGROUND

Lectins displaying blood group specificity are important for blood group typing and antigen recognition. Their use in blood banks is especially widespread in situations where there is a shortage of specific antisera. This report describes the efficiency of Aplysia gonad lectin as a reliable reagent for the detection of I antigen, which is common on adult human cells but reduced in fetal, newborn, and rare adult red cells.

STUDY DESIGN AND METHODS

The selective hemagglutinating activity of the Aplysia lectin was compared with that of human anti-I and several I-reactive lectins, including two plant lectins, one galactophilic microbial lectin, and bovine spleen galectin.

RESULTS

The comparison has revealed that Aplysia gonad lectin, like human anti-I, strongly agglutinates and adsorbs to adult I-positive red cells, differentiating between them and fetal or rare I-negative adult red cells (although with less of a difference). In contrast to the plant and microbial lectins examined, its I-affinity does not depend on the presence of ABH or P system antigens and it clearly detects higher I antigen expression in Oh red cells. The hemagglutinating activity of Aplysia lectin as that of all the I-detecting proteins is enhanced at 4 degrees C, but unlike the human anti-I Aplysia lectin-induced hemagglutination is stable at room temperature.

CONCLUSIONS

The Aplysia lectin is a reliable anti-I reagent, which strongly agglutinates I-positive adult human red cells irrespective of their ABH or P system antigens. This lectin is usable at room temperature.

The hemagglutinating activities of Pseudomonas aeruginosa lectins PA-IL and PA-IIL exhibit opposite temperature profiles due to different receptor types

The two Pseudomonas aeruginosa lectins PA-IL and PA-IIL, which are very similar in subunit size, composition and properties, but differ in carbohydrate specificity, were shown to exhibit opposite temperature profiles in hemagglutination tests. The galactophilic PA-IL, which interacts with the erythrocyte I antigen (together with B or P system antigens), resembles Ii system-specific 'cold hemagglutinins' (including antibodies and lectins of animals and plants) in low (4 degrees C) temperature optimum, while the hemagglutination by the fucose- and mannose-binding PA-IIL (like that of antibodies and lectins which do not bind to these antigens) increases on raising the temperature from 4 to 37 degrees C and even to 42 degrees C. The preferential production of both P. aeruginosa lectins at 28 degrees C and their much stronger interaction with enzyme (protease or sialidase)-damaged cells, as well as the lower temperature optimum (4 degrees C) of PA-IL-binding to the host cells, may be associated with the saprophytic rather than parasitic designation of this bacterium.

Production and characterization of anti-kell monoclonal antibodies using transfected cells as the immunogen

Monoclonal antibodies (Mabs) to blood group antigens are valuable as diagnostic reagents for typing red blood cells (RBCs) in the clinical setting, and for structure-function studies of proteins. Here, we report a powerful system that enabled us to produce Mabs to blood group antigens. A murine erythroleukaemia (MEL) cell line expressing Kell protein, a transmembrane glycoprotein that carries a number of clinically relevant antigens, was used as a novel immunogen. Mabs with different specificities to the Kell protein were produced from a single mouse fusion: an anti-Jsb (MIMA-8), and two antibodies (MIMA-9 and MIMA-10) with novel specificities, that reacted with RBCs with the common Kell phenotype but not with RBCs with K+k- or Kp(a+b-) or K0 phenotypes. The non-reactivity with both K+k- or Kp(a+b-) RBCs implied that the epitope was influenced by the molecular changes associated with an absence of the k or Kpb antigens. MIMA-8 is the first example of a Mab anti-Jsb and was used in the clinical laboratory for screening donor RBCs for Js(b-) blood and for typing RBCs from patients even when the RBCs were coated with anti-IgG as is the case in autoimmune haemolytic anaemia. Heavy and light chain variable regions of MIMA-8 were cloned and the sequence is given. This study illustrates the potential of this novel immunization approach for making monoclonal antibodies to blood group antigens.

Effects of solvent displacement on sensitivity and specificity of monoclonal antibodies for ABO blood grouping of forensic specimens with an absorption-elution test

Using commercially-available monoclonal antibodies (Bioclone, Neo Kokusai, Monoclonal Wako, Gamma Clone and Seraclone), ABO blood grouping of forensic specimens such as bloodstains, salivary stains, seminal stains, nails, hair and cerebral dura mater was performed with an absorption-elution test. Salivary stains, seminal stains and nails were not typed correctly using the antibodies other than Bioclone reagents, while precise grouping of bloodstains was performed using most antibodies. When hair and dura mater were tested, all of the antibodies induced weak or non-specific haemagglutination, hence correct grouping was not achieved. When the antibody solvents were displaced with 5-20% bovine serum albumin in saline, human serum of the group AB donor, or serum of chicken, sheep or bovine, titers of the reagents increased 2-8 times. Hair and dura mater were able to be typed using Bioclone reagents after solvent displacement with human AB or sheep serum, whereas displacement with the other solvents enhanced non-specific reactions.

Cold-induced augmentation of I blood group antigen interactions with galactophilic lectins

The I antigen appears on human cells in the postnatal period, by addition of N-acetyllactosamine (beta 1-6) branching to the fetal i antigen structure, which is specified by linear oligo N-acetyllactosamine (beta 1-3) chain. Concurrently with the I antigen appearance on adult human erythrocytes most human sera exhibit low levels of anti-I agglutinins. These antibodies induce hemagglutination mainly at low temperatures (4 degrees C) and scantly at body temperature. Therefore they were named "cold agglutinins". We have used these antibodies and several hemagglutinating galactophilic animal, plant, and microbial lectins that also react with the I antigen, to study whether the cold-favored agglutination of the I antigen-bearing cells is a peculiar property of the anti-I antibodies or a special trait of that antigen. It has been found that the interactions of all of the examined lectins, irrespective of their source, with the adult human erythrocytes significantly increased at 4 degrees C, in contrast to those of the same cells with diverse I-insensitive antibodies and lectins, which were significantly higher at room temperature.

Surfactants in membrane solubilisation

An understanding of the action of many drugs requires a knowledge of how the drug reaches the site of action in a cell. A detailed knowledge of the structure and function of cell membranes is often required to understand the transport of drugs across the plasma membrane. To obtain this information proteins must be isolated. The isolation and characterisation of cell membrane proteins usually requires the solubilisation of the membrane and a method of separation of the various membrane proteins and glycoproteins. The starting point for such an investigation is the choice of a suitable surfactant (detergent) to solubilise the membrane. This review considers the range of surfactants that are available for membrane solubilisation, how surfactants interact with membranes, the part they play in the separation of integral membrane proteins and in the reconstitution of membrane proteins for functional studies. The solubilisation of specific membrane proteins and glycoproteins including the human erythrocyte anion transporter, mitochondrial porin, sarcoplasmic reticulum Ca(2+)-ATPase, the ATPase-active multidrug transporter P-glycoprotein, bacteriorhodopsin and rhodopsin are also discussed.

Effect of 1-beta-D-arabino-furanosyl-cytosine (ara-C) induction of K562 cells on expression of Rh and other blood group active proteins

K562 cells undergoing differentiation induced by 1-beta-D-arabino-furanosyl-cytosine (ara-C) were examined as a model for studying the biosynthesis and regulation of Rh and other blood group active membrane proteins. Untreated and ara-C-induced K562 cells were analysed for the expression of these proteins using monoclonal antibodies in combination with flow cytometry. The major membrane proteins glycophorins A and C remained unaltered upon induction by ara-C. The display of LFA-3 (CD58) and DAF (CD55) by uninduced K562 was one order of magnitude lower than that of the glycophorins; following ara-C treatment there was a 50% rise in LFA-3 but a modest decrease in the level of DAF expression. The expression by untreated K562 cells of Rh, Lutheran and Kell proteins as well as the Rh D antigen was low, whereas that of CD44 and band 3 protein was negligible. Following induction by ara-C the levels of Rh and Kell proteins rose up to 7- and 3.5-fold respectively, and there was an increase in RhD-antigen expression. In contrast, ara-C induction of K562 cells failed to augment their display of Lutheran, CD44 and band 3 proteins. Analysis of Rh transcripts following the purification and RT-PCR analysis of K562 mRNA showed that uninduced K562 cells contain two distinct mRNAs corresponding to Rh Ce (1.8 kb) and Rh D (3.5 kb). The apparent concentration of each mRNA increased following induction with ara-C. K562 plasma membranes also contained Rh polypeptides as determined by immunoblot analysis using anti-Rh polypeptide rabbit polyclonal sera raised to Rh synthetic peptides. A novel hybrid Rh transcript corresponding to exons 1-4 of RHD and exons 5-10 of RHCE has been cloned and sequenced from ara-C induced K562 cells, and may have arisen by general recombination between the RHD and RHCE genes.

Five monoclonal antibodies against glycophorin A of human erythrocyte recognize glycoprotein of bovine erythrocyte

To study heterophile blood antigens on erythrocytes between human and experimental or domestic animals, we have produced 295 monoclonal antibodies (MAbs) to human erythrocyte membrane protein. According to the affinity, reactivity, and titre of the MAbs, we selected 40 clones to study the heterophile blood antigens between human and bovine, chicken, guinea pig, horse, rabbit, sheep, and swine. Five MAbs commonly reacted with human type A, type B, and type O erythrocytes and reacted with bovine erythrocytes as well but did not react with erythrocytes from other species. Other MAbs did not react with erythrocytes from all the tested animals. These five MAbs reacted with the same erythrocyte membrane protein, 90 KD glycophorin A (GPA) of human or 200 KD major glycoprotein and other two components of bovine by immunoblotting and GPA competitive inhibition assay. Furthermore, by enzyme treatment and monosaccharide competitive inhibition assay, it was confirmed that these five MAbs recognized antigen epitope of glycosylation free amino acid portion but not glycosylation portion of GPA of erythrocyte membrane.

Molecular basis of Kell blood group phenotypes

The molecular basis of different Kell blood group phenotypes is reviewed. Sequence analysis of the Kell gene (KEL) established that single base substitutions, resulting in amino acid changes, are responsible for the different phenotypes. Most of the amino acid substitutions, with the exception of the one responsible for expression of KEL6 (Jsa), occur at the amino-terminal half of the protein, a domain that has least amino acid homology with a family of zinc endopeptidases, which include neutral endopeptidase 24.11 and endothelin-converting enzyme-1. Some of the genes were expressed in transfected cells and typed with alloantibodies to confirm that the identified mutations are responsible for antigen expression. Clinical applications of Kell blood group genotyping which include prenatal diagnosis to monitor hemolytic disease of the newborn are discussed.

Role of Fc gamma RIIa (CD32) in IgG anti-RhD-mediated red cell phagocytosis in vitro

To test the role of Fc gamma RIIa in IgG anti-RhD-mediated phagocytosis three IgG1 and two IgG3 human monoclonal anti-D antibodies were tested for ability to mediate binding/phagocytosis of cDE/cde and -D-/-D- red cells by Fc gamma RIIa-R131 and Fc gamma RIIa-H131 cDNA-transfected 3T6 fibroblasts. Both IgG3 monoclonal antibodies brought about -D-/-D- cell interaction with IIa-transfected fibroblasts, while only one of them, Og3, mediated binding of cDE/cde targets. Although Fc gamma RIIa expression was three times greater on IIa-R131 than on IIa-H131 fibroblasts, the latter bound significantly more Og3-coated cDE/cde- and IgG3 anti-D-sensitized -D-/-D- cells, respectively, than the former effectors and showed some phagocytosis of the -D-/-D- targets. IgG1 anti-D antibodies were inactive in mediating red cell interaction with the fibroblasts. Moreover, monoclonal anti-Fc gamma RII IV.3 partially inhibited the phagocytosis by adult or fetal monocytes of Og3-sensitized cDE/cde cells. Fc gamma RIIa-H/H131 monocytes exhibited higher phagocytic indices towards these targets than monocytes of other IIa allotypes. The results indicate that Fc gamma RIIa can participate in the phagocytosis of red cells coated with IgG3 anti-D; in this case the allotype of the receptor will modify the extent of red cell destruction.

A monoclonal antibody to swine erythrocytes recognizes the B blood group on the major glycophorin

Recently monoclonal antibodies (mAbs) to swine red blood cells have been described. One of them (1AC11) was specific for the major swine glycoprotein with a molecular weight of 45 kDa and another mAb, 2G2, recognized the Ba allele in the B system of swine blood groups. Immunoblotting experiments to characterize the mAb 2G2 indicated that it reacts with an antigen of 45 kDa, present on the aqueous phase, glycophorin fraction, of swine red blood cells with the Ba allele and does not react with BbBb homozygous cells. The antigen recognized by 2G2 has the same characteristics as the major glycophorin recognized by 1AC11, so we can conclude that the B system of the swine blood group is on the major glycophorin of swine erythrocyte membranes.

Characterization of blood-group-ABO(H)-active glycosphingolipids in type-AB human erythrocytes

Neutral glycolipids in Folch's upper phase were isolated from human erythrocyte membranes of 22 individuals with blood type AB. On immunostaining by TLC with anti-A IgG, all reactive glycolipids in type A corresponded to reactive glycolipids in type-AB erythrocytes. With anti-B IgM, all reactive glycolipids in type-B erythrocytes also corresponded to reactive glycolipids in type-AB erythrocytes. By comparison of the reactivity to that of the anti-A and anti-B antibodies, it was found that, in type-AB erythrocytes, all glycolipids reactive with either one of the anti-A or anti-B antibodies were detected in both type-A and type-B erythrocytes, and that A-active glycolipids had higher Rf values than B-active glycolipids on TLC plates. A series of glycolipids reactive with both antibodies were purified from the Folch's upper neutral glycolipid fraction of erythrocyte membranes by column chromatography, and was characterized by TLC-immunostaining and negative secondary-ion mass spectrometry. The results strongly suggested that A-active and B-active carbohydrate chain epitopes existed separately as glycolipid molecules in blood-type-AB erythrocytes. It was also confirmed that these phenotypes observed in erythrocyte membranes were exhibited by blood-group-active glycosphingolipids in the small intestine of blood-type-AB individuals. Furthermore, upon treatment of fractions obtained from silicic acid column chromatography with alpha-N-acetylhexosaminidase or alpha-galactosidase, a branched hybrid-type molecule with both A and B determinants was not detected.

Neutral polymers elicit, and antibodies to spectrin, band 4.1 protein and cytoplasmic domain of band 3 protein inhibit the concanavalin A-mediated agglutination of human erythrocytes

Concanavalin A (Con A) is known to agglutinate human erythrocytes if the cells are pre-treated with a proteinase or neuraminidase. We report that untreated cells can also be made to agglutinate with the lectin if the lectin-bound cells are treated with anti-Con A antibodies, or if a neutral polymer such as serum albumin, polyvinylpyrrolidone or Ficoll is added. Thus, Con A falls in the category of 'incomplete' lectins. The polymer induces Con A-agglutinability without altering the receptor number, or deformability of the cells. If the polymer is sequestered within erythrocyte ghosts, Con A is unable to agglutinate them; but the presence of the polymer only on the outer surface (as in intact cells) or on both the surfaces permits agglutinability. Thus, the site of the polymer effect resides on the outer surface of the membrane. The polymer, however, is unable to induce agglutinability in erythrocyte vesicles, whose membrane lacks skeletal proteins. The result suggests a positive role for the membrane skeleton in the process of agglutination brought about by the polymer, as is true also for the agglutination of proteinase-treated cells. In order to obtain detailed information on the proteins participating in agglutination, monospecific antibodies to spectrins, band 4.1 protein, ankyrin and the cytoplasmic domain of band 3 protein were internalized in erythrocytes. It is found that anti-spectrin and anti-band 3 cytoplasmic domain, but not their Fab's, inhibit the Con A-mediated agglutinability partially, and anti-4.1 antibodies, as well as the Fab's, inhibit the agglutinability substantially. Anti-ankyrin, however, was without any effect. The results confirm a positive role for the membrane skeleton in the Con A-mediated agglutination of normal erythrocytes in the presence of a neutral polymer, or in proteinase treated cells. We also provide evidence for requirement of Mg-ATP in the agglutination process.

The surface properties of phospholipid liposome systems and their characterisation

The field of liposome (vesicle) research has expanded considerably over the last 30 years. In physical chemical terms liposomes have many of the characteristics of colloidal particles and their stability is determined in part by the classical surface forces. It is now possible to engineer a wide range of liposomes varying in size, phospholipid composition and surface characteristics. The surfaces of liposomes can be modified by the choice of bilayer lipid as well as by the incorporation and covalent linkage of proteins (e.g. antibodies and sugar binding proteins [lectins]), glycoproteins and synthetic polymers. Much of the impetus for liposome design has come from their potential value as drug delivery systems. The development of technologies for the production of such a range of liposome systems has presented interesting problems in the characterisation of their properties. The review addresses the progress that has been made in characterising the surfaces of different types of liposomes with specific reference to their electrophoretic properties and their interpretation and the physical interactions between liposomal bilayers.

What is important on the red blood cell surface

Blood group antigens have provided tools for investigation of the red cell surface and been very useful as genetic markers in family, population and forensic studies. Precise definition of phenotypes is very important. Application of MAIEA (monoclonal antibody-specific immobilisation of erythrocyte antigen), a recently reported technique, to identify antigens and to assign red cell antigens to a particular membrane component is described: location of Knops system antigens on CR1 is confirmed and provisional assignment of Cromer system antigens to the different short consensus regions of decay accelerating factor (DAF) is described. Variability of red cell antigen expression is considered. The possibility is discussed that factors other than alterations in Rh genes may be responsible for some Rh variant phenotypes. Some C variants, two of which are associated with low incidence antigens, are described. The relationship of Xga with the quantitative polymorphism of 12E7 antigen is reconsidered in light of some recent immunochemical studies.

Nonlethal adherence to human neutrophils mediated by Dr antigen-specific adhesins of Escherichia coli

Uropathogenic Escherichia coli strains express a variety of adhesins, including members of the Dr adhesin family such as the Dr hemagglutinin, AFAI, and AFAIII. Certain E. coli adhesins (e.g., type 1 and S fimbriae) are known to mediate adherence to human polymorphonuclear leukocytes (PMNs). The receptor on erythrocytes for Dr family adhesins, decay accelerating factor, is also present on PMNs. To determine whether Dr family adhesins mediate adherence to PMNs and to characterize the specificity and consequences of such adherence, we studied agglutination of PMNs and adherence to PMNs by recombinant E. coli strains expressing various mannose-resistant or mannose-sensitive adhesins, in the presence or absence of inhibitors of adherence. Dr family adhesins, like type 1 fimbriae, mediated concentration-dependent adherence to PMNs. Adherence to PMNs was mannose sensitive for type 1 fimbriae but mannose resistant for Dr family adhesins. Chloramphenicol inhibited PMN adherence for the Dr hemagglutinin with the same potency as that with which it inhibited hemagglutination, but it was inactive against PMN adherence and hemagglutination mediated by other members of the Dr adhesin family. In contrast to PMN adherence mediated by type 1 fimbriae, adherence mediated by the Dr hemagglutinin did not lead to significantly increased bacterial killing. These data suggest that Dr family adhesins mediate a novel pattern of adherence to PMNs, probably by recognizing decay accelerating factor, with minimal consequent bacterial killing.

Differential splicing of the glycophorin A mRNA

Two truncated mRNAs, in contrast to the full length of mRNA associated with the glycophorin A gene (GpA-TI, GpA-TII), were isolated from erythroid cells cultured by the selective two-phase liquid culture system for erythroid progenitors in peripheral blood from a normal individual. The GpA-TI mRNAs displayed a direct transition from exon I to exon III, so that the deletion of exon II resulted in the deletion of 33 amino acids encoded by this exon. Furthermore, the GpA-TII showed two direct transitions from exon I to exon III and from exon III to the exon V of the GpA gene. This mRNA lacked both exons II and VI, resulting in the deletion of 46 amino acids. Is is concluded that these truncated mRNAs are transcribed from the same gene as the GpA gene and correspond to splicing isoforms lacking different exons.

Some concepts relating to the molecular genetic basis of certain MNS blood group antigens

The unfolding story of genes encoding variant glycophorin molecules is already known to be more complicated than described here. The principles outlined provide a basis for understanding the fundamental events that occur in genes encoding the glycophorins as well as genes encoding unrelated proteins carrying other blood group antigens. Over 20 different genes involving the GYPA and GYPB family have been described. These genes arise from gene rearrangements within a relatively short region. This hot spot of activity has inverted palindromic sequences, which are known to be sites for DNA recombination. Similar structures exist in the major histocompatibility complex (MHC) where allelic diversity is a functional requisite. However, the significance of allelic diversity in the glycophorin gene family is not understood. The GYPA, GYPB and GYPE gene cluster is known to be prone to mutation by radiation because there is a high incidence of somatic mutation events in atomic bomb survivors, in people exposed to accidental radiation, in patients with Bloom's syndrome and in patients receiving radiation therapy. The mutation events were dose dependent: the greater the exposure, the greater proportion of red blood cells exhibited mutations. While it is known that MHC diversity protects against infection, the reason for glycophorin rearrangements remains to be determined.

Blood group antigens on human erythrocytes-distribution, structure and possible functions

Human erythrocyte blood group antigens can be broadly divided into carbohydrates and proteins. The carbohydrate-dependent antigens (e.g., ABH, Lewis, Ii, P1, P-related, T and Tn) are covalently attached to proteins and/or sphingolipids, which are also widely distributed in body fluids, normal tissues and tumors. Blood group gene-specific glycosyltransferase regulate the synthesis of these antigens. Protein-dependent blood group antigens (e.g., MNSs, Gerbich, Rh, Kell, Duffy and Cromer-related) are carried on proteins, glycoproteins and proteins with glycosylphosphatidylinositol anchor. The functions of these molecules on human erythrocytes remain unknown; some of them may be involved in maintaining the erythrocyte shape. This review describes the distribution, structures and probable biological functions of some of these antigens in normal and pathological conditions.

Role of N-glycosylation in the expression of human band 3-mediated anion transport

The human erythrocyte anion transporter (band 3; AE1) has a single N-linked glycosylation site at amino residue Asn-642. To investigate the functional role of the N-glycan in band 3 (b3) we have constructed mutant b3 cDNAs in which this residue has been replaced by Gly, Ser or Thr, and the expression of these mutants was examined in Xenopus oocytes. Chymotrypsin treatment of intact oocytes was used to assess surface b3. Similar amounts of cleavage were observed with both glycosylated and unglycosylated b3. Greater cleavage of b3 was obtained when human red cell glycophorin A (GPA) was co-expressed with either glycosylated or unglycosylated b3. The co-expression of GPA with either glycosylated or unglycosylated b3 increased the stilbene disulphonate-sensitive chloride transport into oocytes at low cRNA concentrations. In both the presence or absence of GPA, a higher b3-mediated chloride influx into oocytes was observed on expression of glycosylated b3 cRNA compared with similar amounts of unglycosylated b3 cRNA. We suggest that glycosylation is not essential for the expression of functional b3 in oocytes, but may play a role in enabling the protein to acquire its correct folding with the highest anion transport activity.

Anti-pig IgM antibodies in human serum react predominantly with Gal(alpha 1-3)Gal epitopes

A major problem with pig-to-human-tissue xenograft studies is that humans have natural antibodies to pig cells; these antibodies would cause hyperacute rejection if pig tissues were xenografted to humans. Here we show that most of human IgM antibodies present in the serum of healthy donors and reactive with pig cells react with galactose in an (alpha 1-3) linkage with galactose--i.e., Gal(alpha 1-3)Gal. Absorption studies demonstrated that the antibodies detected the same or similar epitopes on the surface of pig erythrocytes, blood and splenic lymphocytes, and aortic endothelial cells (EC). The antibodies were sensitive to 2-mercaptoethanol (2ME) treatment, did not bind to protein A or G, and were present in the high molecular weight fraction of serum; they are clearly IgM antibodies. Further, the antibodies did not react with human ABO blood group substances and are not related to human blood group A or B, which carry a terminal galactose. The reaction of human serum with pig erythrocytes was specifically inhibited by mono- and disaccharides: D-galactose, melibiose, stachyose, methyl-alpha-D-galactopyranoside, and D-galactosamine but not by D-glucose or methyl-beta-D-galactopyranoside; demonstrating that the reaction is with galactose in an alpha and not a beta linkage. A cDNA clone encoding the murine alpha-1,3-galactosyltransferase (which transfers a terminal galactose residue with an (alpha 1-3) linkage to a subterminal galactose) was isolated by polymerase chain reaction (PCR), cloned, and transfected into COS cells, which are of Old World monkey origin and, like humans, do not express Gal(alpha 1-3)Gal. After transfection, COS cells became strongly reactive with human serum and with IB4 lectin [which reacts only with Gal(alpha 1-3)Gal]; this reactivity could be removed by absorption with pig erythrocytes. As most of the antibody reacting with pig cells can be removed by absorption with either melibiose or Gal(alpha 1-3)Gal+ COS cells, most of these react with Gal(alpha 1-3)Gal. These findings provide the basis for genetic manipulation of the pig alpha-1,3-galactosyltransferase for future transplantation studies.