I-int phenotype among three individuals of a Parsi community from Mumbai, India.

The red blood cells (RBCs) of most adult individuals display an I+i- phenotype, whereas those of newborns and some rare adult individuals are typed as I-i+. The phenotype in the latter category, designated as adult i, is under genetic influence as the RBCs of I+i+ individuals display strengths of I and i antigen expression intermediate to that of ordinary adults and ii-adults. As there was no information on the occurrence of adult i phenotype in the Indian population, the present study was undertaken. The RBCs of randomly selected subjects were screened with anti-I and anti-i reagents by a saline tube technique at 220C. Individuals with unusual I and i antigen reactivity patterns were further tested by a semi-quantitative method with a battery of anti-I and anti-i reagents, followed by family studies. Three of the 5864 donors tested showed an elevated strength of i antigen. Further study revealed an intermediate strength of both I and i antigens compared with those on RBCs from adult and cord blood samples. All three probands came from an ethnic Parsi community. The phenotype (referred to as I-int) was shown to be inherited, being passed through two generations, but none of the members of the families had displayed an adult i phenotype. The I-int phenotype detected showed an ethnic association because all three subjects belonged to an endogamous Parsi community that has migrated to India some centuries ago from Persia, the present-day Iran.

H-deficient Bombay and para-Bombay red blood cells are most strongly agglutinated by the galactophilic lectins of Aplysia and Pseudomonas aeruginosa that detect I and P1 antigens.

The galactophilic lectins Aplysia gonad lectin (AGL) and Pseudomonas aeruginosa lectin (PA-IL), which detect human I and P1 RBC antigens, were examined for hemagglutination of H+ (group O and B) and H-deficient (Bombay and para-Bombay phenotype) RBCs. The results were compared with those obtained using two other galactophilic lectins, Maclura pomifera lectin (MPL) and Arachis hypogaea (peanut) agglutinin (PNA), which share T-antigen affinity, and two fucose-binding H-specific lectins, Ulex europaeus (UEA-I) and Pseudomonas aeruginosa lectin (PA-IIL), as well as with those achieved with anti-I serum. The results revealed that, in contrast to UEA-I and PA-IIL, which preferentially agglutinated H+ RBCs, and to MPL and PNA, which similarly agglutinated all examined RBCs, AGL, PA-IL, and the anti-I serum agglutinated the H-deficient RBCs more strongly than did the H+ RBCs. These findings could be attributed to increased levels of I and P1 antigens on those RBCs resulting from the use of the free common H-type 2 precursor for their synthesis. Since both PA-IL and PA-IIL are regarded as potential pathogen adhesins, it would be interesting to statistically compare the sensitivities of individuals of H+ and H-deficient RBC populations to P. aeruginosa infections.

Grupos sanguíneos y enfermedad / Blood groups and disease

La membrana eritrocitaria sirvió como modelo general para el conocimiento de la membrana plasmática. Algunas de sus estructuras son antígenos pertenecientes a los sistemas de grupos sanguíneos y están siendo caracterizadas molecular y funcionalmente como receptores, transportadores o enzimas, incluso como puertas de entrada para patógenos. Así, el Plasmodium vivax (causante de la malaria) requiere la glucoproteína Duffy para penetrar en el interior de los hematíes humanos, y el antígeno principal del sistema P (P1) es también el receptor para el acceso del parvovirus B19. Estos antígenos no siempre se limitan a los glóbulos rojos, sino que pueden influir en diversos tejidos, el plasma o las secreciones con importantes relaciones patogénicas. Ciertas cepas agresivas de Eschirichia coli precisan antígeno P1 para anclarse al epitelio urinario, el antígeno Lewis(b) es el receptor de Helicobacter pylori en la mucosa gástrica, el anti-B de los sujetos con los grupos sanguíneos O y A podría ayudarles a combatir las bacteriemias por E. coli, el grupo Lewis condiciona las concentraciones séricas de CA-19.9 y el efecto protector de la leche materna. Sin embargo, la principal influencia sería la hipocoagulabilidad observada en la población de grupo O (valores inferiores de factor VIII) asociada con una prevalencia menor de enfermedades tromboembólicas

The erythrocyte membrane was used as general model for the plasma membrane knowledge. Some of their structures are antigens from blood group systems being characterized at molecular and functional level as specific receptors, transporters or enzymes, even receptors for infectious agents. Plasmodium vivax malarial parasites require the Duffy blood group glycoprotein to penetrate into human red blood cells and the main antigen of P system (P1) is also the Parvovirus B19 receptor. Furthermore, these substances have an effect on several tissues, plasma and secretions involving pathogenic relationships. Certain aggressive Escherichia coli strains require the P1 antigen to attach to the urothelial cells, the Lewis(b) antigen is the gastric receptor for H. pylori, the anti-B from O or A individuals might protect them against the sepsis produced by E. coli, the Lewis group determines the CA-19.9 serum levels or the protective effect of breast milk. However, the most important effect could be the plasma hypocoagulability observed among the O blood group population (with lower factor VIII levels) in association with a reduced prevalence of thromboembolic diseases

A nonsense mutation in the glucosaminyl (N-acetyl) transferase 2 gene (GCNT2): association with autosomal recessive congenital cataracts.

PURPOSE: To identify the genetic defect associated with autosomal recessive congenital cataract in four Arab families from Israel. METHODS: Genotyping was performed using microsatellite markers spaced at approximately 10 cM intervals. Two-point lod scores were calculated using MLINK of the LINKAGE program package. Mutation analysis of the glucosaminyl (N-acetyl) transferase 2 gene (GCNT2) gene was performed by direct sequencing of PCR-amplified exons. RESULTS: The cataract locus was mapped to a 13.0-cM interval between D6S470 and D6S289 on Chr. 6p24. A maximum two-point lod score of 8.75 at theta = 0.019 was obtained with marker D6S470. Sequencing exons of the GCNT2 gene, mutations of which have been associated with cataracts and the i blood group phenotype, revealed in these families a homozygous G-->A substitution in base 58 of exon-2, resulting in the formation of premature stop codons W328X, W326X, and W328X, of the GCNT2A, -B, and -C isoforms, respectively. Subsequent blood typing of affected family members confirmed the possession of the rare adult i blood group phenotype. CONCLUSIONS: A nonsense mutation in the GCNT2 gene isoforms is associated with autosomal recessive congenital cataract in four distantly related Arab families from Israel. These findings provide further insight into the dual role of the I-branching GCNT2 gene in the lens and in reticulocytes.

Extracellular matrix components of the placental extravillous trophoblast: immunocytochemistry and ultrastructural distribution.

Invasive extravillous trophoblast cells of the human placenta are embedded in a self-secreted extracellular matrix, the matrix-type fibrinoid. The ultrastructure and molecular composition of the matrix-type fibrinoid of the term human placenta were studied by transmission electron microscopy and immunogold labelling. We used antibodies directed against different matrix proteins such as collagen type IV, laminin, vitronectin, heparan sulfate, various fibronectin isoforms, and against the oncofetal blood group antigen, "i". Immunogold labelling patterns of matrix proteins are the basis for the subdivision of the trophoblast-derived matrix-type fibrinoid into mosaic-like patches of structurally and immunocytochemically different compartments. Firstly, fine granular patches with structural similarities to basal lamina material are composed solely of collagen type IV and laminin. Secondly, an ultrastructurally amorphous glossy substance shows reactivity with antibodies against heparan sulfate and vitronectin. A third type of patches, fine fibrillar networks embedded in the above-mentioned glossy matrix, are reactive with antibodies against normal fibronectin isoforms (IST-4, IST-6, IST-9) and oncofetal isoforms (BC-1, FDC-6). The blood group precursor antigen "i" was not only expressed on the surfaces of the extravillous trophoblast cells but was associated with the fibronectin-positive fibrils. In conclusion, within this extracellular matrix, clear compartments of different composition can be distinguished from each other. Glycosylation with "i" in this matrix may be involved in immunological masking, thus preventing rejection of placenta and fetus.

Structure elucidation of blood group B-like and I-active ceramide eicosa- and pentacosasaccharides from rabbit erythrocyte membranes by combined gas chromatography-mass spectrometry; electron-impact and fast-atom-bombardment mass spectrometry; and two-dimensional correlated, relayed-coherence transfer, and nuclear Overhauser effect 500-MHz 1H-n.m.r. spectroscopy.

The structures of two glycosphingolipids, a ceramide eicosasaccharide BIrab-3 and a ceramide pentacosasaccharide BIrab-4 with "B-like" and distinct I blood-group activity, isolated in high yield from rabbit erythrocyte membranes, were investigated. The determination of their general structure, alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)- [alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-Glcp-NAc-(1----6)]-be ta- D-Galp-(1----n4)-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-beta-D-Gl cp- (1----1)-ceramide, with n = 3 for BIrab-3 and n = 4 for BIrab-4, was based on the results of methylation analysis, fast-atom-bombardment and electron-impact mass spectrometry, 1D and 2D COSY, RCT, and n.O.e. 1H-N.m.r. spectra, and specific enzymic and chemical degradation.

An immunosorbent assay for blood group I antigens in breast carcinoma.

Tumor cells elaborate and release into the circulation a variety of glycoproteins. An enzyme-linked immunosorbent assay (ELISA) was developed to monitor carbohydrate structures secreted into the circulation. Among these antigens are the structures specific for the blood group I antigens, which are incompletely converted to ABH antigens on the membranes of tumor cells. The I antigens in the sera of 67 women with breast carcinoma (BCa), 58 with benign breast disease (BBD), and 47 controls were measured by the ELISA. In this assay, I antigen from ovarian cyst mucin was bound to the wells of polystyrene microtiter plates. The monoclonal human anti-I antibody (Hy) was added to the wells along with perchloric acid extracts of patient and control sera at five different dilutions. The anti-I binding to the solid-phase I antigen was determined after incubation steps with peroxidase-labeled anti-human IgM and substrate. The amount of sera extracts giving 50% inhibition of anti-I (Hy) binding was determined from the inhibition curves which were corrected by integrating the slope values into that of the standard curve obtained with extracts of normal sera. The I antigens were significantly higher in pathologic stage (PS) IV sera (P less than 0.001), and comparable in PS I, PS II, and PS III and BBD sera to those in control sera. The anti-I (Hy) binds strongly Gal 1,4 GlcNAc 1,6 Gal (alpha GalNAc); Gal 1,4 GlcNAc 1,6 (Gal 1,4 GlcNAc 1,3) Gal; and to a lesser extent Gal 1,4 GlcNAc 1,3 Gal 1,4 GlcNAc (0.06, 0.09, and 0.35 mM, giving 50% inhibition, respectively). It was concluded that similar or related structures may be expressed on the membrane of metastatic BCa cells.

Blood group antigens A, B, H, Lea, Leb, and I(Ma) in resting and tetragastrin stimulated gastric juice of patients with non-neoplastic diseases of the stomach.

In view of the anomalous expression of blood group and related antigens in the gastric mucosae of patients with malignant and premalignant diseases of the stomach, and the potential clinical value of their measurement, a preliminary study has been performed on the blood group antigens A, B, H, Lea, Leb, and I(Ma) in glycoprotein rich extracts of the resting and tetragastrin stimulated gastric juice of patients without evidence of gastric cancer. The aim has been to assess whether the antigenic profiles known to distinguish the gastric mucosae of secretors from those of non-secretors are reflected in the glycoproteins of gastric juice. Antigenic profiles which distinguish secretors from non-secretors were observed in the stimulated rather than the resting gastric juice as follows: the A, B or H antigens but not I(Ma) were strongly expressed in the glycoproteins of secretors, while I(Ma) was the antigen characteristic of non-secretors. On the other hand, there was considerable overlap in the Lea and Leb antigen values in the resting and stimulated gastric juice of secretors and non-secretors. Among these antigens, I(Ma) is known to appear as a neo-antigen in the gastric mucosae of secretors with malignant and premalignant diseases of the stomach. Thus this antigenic determinant is potentially a clinically useful marker in the gastric juice of 75% of the population who are secretors. The clinical value of the levels of this antigen in the gastric juice now deserves investigation.

Microenvironmental immunoregulation: possible role of contrasuppressor cells in maintaining immune responses in gut-associated lymphoid tissues.

The addition of Peyer's patch T cells from most strains of mice to spleen cells in primary Mishell-Dutton cultures either has no effect or augments the spleen cells' response to sheep erythrocytes. However, if the Peyer's patch T cells are treated with an anti-I-J antiserum and complement to remove contrasuppressor-inducer cells, the remaining Ly-2 cells (T cells that express Ly-2 but not Ly-1) are highly suppressive. This "latent" suppressor cell activity also can be revealed by removing contrasuppressor-acceptor (transducer) cells from the splenic assay population with either an anti-I-J or anti-Ly-2 antiserum. These findings, taken together with previous work showing that orally administered antigen leads to systemic tolerance, give experimental support to the notion that contrasuppression may be important in allowing microenvironmental immune responses (in this case the gut-associated lymphoid tissue) to take place while systemic immunity is suppressed.