F-statistics and analysis of gene diversity in subdivided populations

It is show that Wright's F-statistics can be defined as ratios of gene diversities of heterozygosities rather than as the correlations of uniting gametes. This definition is applicable irrespective of the number of alleles involved or whether there is selection or not. The relationship between F-statistics and Nei's gene diversity analysis is discussed.

Structural comparison of glycophorins and immunochemical analysis of genetic variants

Differences in amino acid sequence of erythrocyte membrane glycophorin A are correlated with M or N blood group activity. A second sialoglycoprotein, glycophorin B, has an amino acid sequence identical to that of glycophorin AN in the first 23 positions and carries N activity only, suggesting that different structural genes code for the glycoproteins carrying these antigens. Certain genetically variant cells lack glycophorin A, as determined by immunochemical methods, and serological MN activity. Other variants lack MN activity, but contain normal amounts of glycophorin A in the membrane.

Blood group MN precursors as human breast carcinoma-associated antigens and "naturally" occurring human cytotoxins against them

Blood groups MN active substances were found in benign and malignant human mammary glands. However, the precursor T (Thomsen-Friedenreich) antigen, as determined with human sera, occurred in all cancerous breast tissues tested but not in the benign mammary glands. Anti-T antibody, which is present in all human sera, was severely depressed in 21.16% of 189 breast carcinoma patients, compared with 3.62% of 470 persons of similar age without cancer. Of 720 persons tested approximately 85% of those with severely depressed anti-T had carcinoma; their IgG, IgM and IgA concentrations were of normal range. A greater than 25%-90% increase in anti-T titer score was found in 65.6% of 32 patients bled 1-14 months after mastectomy for carcinoma as compared with 3.1% of 32 patients with breast biopsy who had no carcinoma. All differences in anti-T titer score changes reported are statistically highly significant. Injection of T antigen from human erythrocytes increased anti-T titer scores.

Blood group precursor T-antigen expression in human urinary bladder carcinoma

Tumor deletion of the ABH blood group antigens (BGAg) heralds an unfavorable prognosis in human bladder cancer. The T antigen (Thomsen-Friedenreich antigen: TAg), a precursor of other BGAg, has previously been found in malignant but not most normal cells, in which the TAg is cryptic but can be unmasked with neuraminidase (NMD). We investigated the prognostic significance of TAg expression in bladder cancer by staining paraffin sections with a T-specific lectin (peanut agglutinin [PNA]) immunoperoxidase technic. Seventy-two cases of low grade, low stage bladder cancer, 21 cases of high grade bladder cancer, and 68 controls were studied. All normals expressed the TAg only after NMD treatment (Cryptic TAg+). The Grade III cancers, all invasive, either expressed the TAg (TAg+)(67%) or lacked T even after NMD (Cryptic TAg-) (29%), indicating that the T structure was lost rather than masked as in normal tissue. Thirty-nine per cent of 23 Grade I and II cancers which were TAg+ or Cryptic TAg- subsequently became invasive (Stage B), compared with 10% of 49 Cryptic TAg+ cancers. For 32 Grade I and II, ABH BGAg negative cancers, 64% of TAg+ or Cryptic TAg- cancers became invasive, compared with 17% of cancers which had Cryptic TAg+. Thus, the TAg may be a prognostically useful immunohistochemical tumor marker in bladder cancer, especially for tumors negative for ABH BGAg.

The membrane change in En(a-) human erythrocytes. Absence of the major erythrocyte sialoglycoprotein

We investigated the membrane of En(a-) human erythrocytes as part of a study of the structure and biochemical function of the surface glycoproteins of the mammalian cell. 2. En(a-) erythrocytes were selected because they have more extensive changes at the cell surface than any other known erythrocyte variant. 3. Our results show that in En(a-) erythrocytes: (a) the major membrane sialoglycoprotein is lacking; (b) the other major membrane-penetrating glycoprotein (band 3) has an altered electrophoretic mobility. 4. The apparent clinical normality of En(a-) cells suggests that the change in band 3 may compensate for the loss of the membrane sialoglycoproteins. It is clear that a viable erythrocyte can exist despite the absence of one of its major surface components.

Abnormal blood-group-Ss-active sialoglycoproteins in the membrane of Miltenberger class III, IV and V human erythrocytes

1. We have studied the inherited changes occurring in the sialoglycoproteins of membranes from erythrocytes of type Miltenberger Class III (Mi.III), Miltenberger Class IV (Mi.IV) and Miltenberger Class V (Mi.V) by using sodium dodecyl sulphate/polyacrylamide gel electrophoresis and lactoperoxidase radioiodination. 2. Mi.III erythrocytes lack the normal blood-group-Ss-active sialoglycoprotein but contain an unusual s-active sialoglycoprotein of higher apparent molecular weight. A similar abnormal S-active sialoglycoprotein appears to occur in Mi.IV erythrocytes. 3. The Mi.V condition is associated with the hemizygous absence of both the normal blood-group-MN-active sialoglycoprotein and the normal Ss-active sialoglycorprotein. However, a new sialoglycoprotein component is present in these cells that has properties characteristic of both the MN-active and Ss-active sialoglycoproteins. 4. Our results suggest that the new sialoglycorportein present in Mi.V erythrocytes is a hybrid of the normal MN sialoglycoprotein and an s-active sialoglycoprotein that has properties similar to the s-active sialoglycoprotein found in Mi.III erythrocytes. We suggest that the unusual Mi.V sialoglycoprotein is derived from chromosomal misalignment with unequal crossing-over between the genes for the MN- and Ss-active sialoglycoproteins in a manner similar to that which gives rise to haemoglobin Lepore. 5. Further studies of S-s-erythrocytes confirm that these cells lack normal Ss-active sialoglycoprotein, but contain an unusual component that shows some of the properties of the normal Ss-active sialoglycoprotein. 6. Analysis of erythrocytes of type Mk/Mi.III confirms that, in addition to the known hemizygous lack of the MN-active sialoglycoprotein, the Mk condition is also associated with a loss of the Ss-active sialoglycoprotein. 7. In order to facilitate discussion of the complex changes that occur in these variant erythrocytes, a new unified nomenclature is used for the erythrocyte sialoglycoproteins.

Different N-terminal amino acids in the MN-glycoprotein from MM and NN erythrocytes

The major human erythrocyte membrane (MN-) sialoglycoprotein was purified from MM, MN and NN cells using detergent gel and ion exchange chromatography. N-terminal analyses with dansyl-chloride revealed serine in preparations from MM and leucine in those from NN erythrocytes, whereas glycoprotein isolated from MN cells contained both the above amino acids. These data strongly suggest that the above residues may represent the structural difference between the M and N antigens. Evidence was also obtained that the Ss-glycoprotein, which is associated with "N" activity, exhibits the same N-terminal amino acid (leucine) as the MN glycoprotein from NN cells.

Identification of two new hemagglutinins of Escherichia coli, N-acetyl-D-glucosamine-specific fimbriae and a blood group M-specific agglutinin, by cloning the corresponding genes in Escherichia coli K-12

Genes encoding the Escherichia coli IH11165 hemagglutinins with specificity for terminal N-acetyl-D-glucosamine and blood group M antigen, respectively, were cloned by a cosmid cloning procedure. A 22-kilobase-pair subclone expressed both hemagglutination specificities in the nonhemagglutinating E. coli HB101 recipient strain. Derivatives obtained by insertion and deletion mutagenesis expressed either one of the two hemagglutination specificities. Both agglutinins were purified; the agglutinin recognizing terminal N-acetyl-D-glucosamine was associated with a new type of fimbria (G fimbria) with an apparent subunit molecular mass of 19.5 kilodaltons, whereas the blood group M agglutinin (M agglutinin) was nonfimbrial and had an apparent subunit mass of 21 kilodaltons.

Post-transfusion alloimmunization in patients with sickle cell disease

The transfusion histories over a 33-month period of 50 patients with sickle cell disease were reviewed to determine the frequency of alloimmunization to red cell antigens following transfusion in these patients. There were 30 females and 20 males, aged 19--49 years. Eighteen (36%) were immunized of which thirteen were females. Five of the patients have formed only one antibody so far, while the other 13 have formed two or more. Thirty-six antibodies were identified: 16 against various Rh antigens, 12 anti-Lewis, 5 anti-Kell and one each of anti-Jka, -Fya and -M. The immunized patients received, on the average, more transfusions although there was a considerable degree of overlap between the immunized and nonimmunized groups. An approach to the hemotherapy of patients with sickle cell disease (SCD) is discussed.

Structural properties of the human MN blood group antigen receptor sites

It is shown that the MN blood group antigen determinant of the major human erythrocyte membrane (MN) sialoglycoprotein is located on its N-terminal octaglycopeptide. The only analytically detectable difference between peptides from MM and NN cells are Ser/Leu and Gly/Glu polymorphisms at the first and fifth positions, respectively. Destruction of the antigens by removal of the N-terminal residues suggests that these amino acids represent a part of the receptor areas for various anti-M or -N reagents. Evidence is presented that the N-terminal structure of the Ss glycoprotein is identical with that of MN glycoprotein from NN red cells up to the fifth residue. This provides an explanation for the 'N' antigen on this molecule and direct support for the earlier proposal that the MNSs locus is represented by homologous genes.

Immunochemical characterization of cyanogen bromide degradation products of M and N blood-group glycopeptides

The major glycopeptides purified from the tryptic digests of M and N blood-group glycoproteins were degraded with cyanogen bromide into two fragments. The chemical composition and serological activities of the fragments obtained were determined. The results show that M and N blood-group determinants are located on the smaller N-terminal fragments, containing 8 amino acid residues and only alkali-labile oligosaccharide chains. Two of 8 amino acid residues are different in M-specific and N-specific glycopeptide. All glycopeptides obtained inhibited Vicia graminea anti-N lectin, but the N-terminal fragment of N-glycopeptide was a better inhibitor than others. Treatment with neuraminidase or acetylation of amino groups destroyed the M and N blood-group activity and increased the activity towards Vicia graminea anti-N lectin of all glycopeptides studied.

Cytostructural localization of a tumor-associated antigen

Tumor cell membrane glycoproteins may be involved in the induction of tumor immunity or in the escape of tumors from immunologic defense mechanisms. Forty-four benign and malignant breast lesions were examined for the presence of a carbohydrate precursor antigen (T antigen) of the human blood group system MN. T antigen was demonstrated by means of an immunohistochemical technique to detect tissue binding of peanut agglutinin, a plant lectin, with affinity for T antigen. Malignant breast lesions showed a pattern of T antigen expression different from that of benign breast tissues. A possible role for T antigen in the modulation of the immune response to breast carcinoma is suggested.

The manual polybrene test: a simple and rapid procedure for detection of red cell antibodies

A rapid manual Polybrene test for detection of red blood cell antibodies have been devised which uses standard laboratory equipment. Red blood cells are incubated with the test sera in a low ionic medium at room temperature for one minute. Polybrene, a quaternary ammonium polymer, is then introduced to cause nonspecific red blood cell aggregation. The test tubes are centrifuged, the cell free supernatant fluid decanted, and the Polybrene effect on the cells is neutralized by adding a dilute sodium citrate-glucose solution. The hemagglutination results are evaluated macroscopically and microscopically. The entire procedure is completed in less than three minutes. In the Rh system, the test is 10--160-fold more sensitive than the antiglobulin reaction. In other systems tested, except for the Kell, a high sensitivity is achieved. The sensitivity for the Kell system is markedly increased, however, by performing a supplementary antiglobulin reaction on the sensitized, Polybrene-treated, red blood cells. The antiglobulin reagent used for this purpose should lack anti-C4 and anti-C3 activities. Sensitivity for cold reactive antibodies is augmented by cooling the cells for 30 seconds before citrate-glucose reagent is added.

Human erythrocyte glycophorins: protein and gene structure analyses

Human RBCs glycophorins are integral membrane proteins rich in sialic acids that carry blood group antigenic determinants and serve as ligands for viruses, bacteria, and parasites. These molecules have long been used as a general model of membrane proteins and as markers to study normal and pathological differentiation of the erythroid tissue. The RBC glycophorins known as GPA, GPB, GPC, GPD, and GPE have recently been fully characterized at both the protein and the DNA levels, and these studies have demonstrated conclusively that these molecules can be subdivided into two groups that are distinguished by distinct properties. The first group includes the major proteins GPA and GPB, which carry the MN and Ss blood group antigens, respectively, and a recently characterized protein, GPE, presumably expressed at a low level on RBCs. All three proteins are structurally homologous and are essentially erythroid specific. The respective genes are also strikingly homologous up to a transition site defined by an Alu repeat sequence located about 1 Kb downstream from the exon encoding the transmembrane regions. Downstream of the transition site, the GPB and GPE sequences are still homologous, but diverge completely from those of GPA. The three glycophorin genes are organized in tandem on chromosome 4q28-q31, and define a small gene cluster that presumably evolved by duplication from a common ancestral gene. Most likely two sequential duplications occurred, the first, about 9 to 35 million years ago, generated a direct precursor of the GPA gene, and the second, about 5 to 21 million years ago, generated the GPB and GPE genes and that involved a gene that acquired its specific 3' end by homologous recombination through Alu repeats. Numerous variants of GPA and GPB usually detected by abnormal expression of the blood group MNSs antigens are known. An increasing number of these variants have been structurally defined by protein and molecular genetic analyses, and have been shown to result from point mutations, gene deletions, hybrid gene fusion products generated by unequal crossing-over (not at Alu repeats), and microconversion events. The second group of RBC membrane glycophorins includes the minor proteins GPC and GPD both of which carry blood group Gerbich antigens. Protein and nucleic acid analysis indicated that GPD is a truncated form of GPC in its N-terminal region, and that both proteins are produced by a unique gene called GE (Gerbich), which is present as a single copy per haploid genome and is located on chromosome 2q14-q21.(ABSTRACT TRUNCATED AT 400 WORDS)

Structure of the Ss blood group antigens. I. Isolation of Ss-active glycopeptides and differentiation of the antigens by modification of methionine

The Ss blood group antigen determinants were found to be associated with the N-terminal tryptic and chymotryptic glycopeptides (residues 1--35 or 1--32) of the Ss sialoglycoprotein from human erythrocyte membranes. The N-terminal portion (residues 1--26) of these peptides is largely identical with that of the MN sialoglycoprotein. Therefore, and since the Ss activity of tryptic glycopeptides was higher than that of chymotryptic fragments, it is concluded that the structural difference between the S and s antigens is located on the C-terminal part (residues 27--32) of these peptides. Chemical modification of sialoglycoproteins by various methods suggests that Glu residue(s) (positions 29 or 28, 31) and possibly alpha-GalNAc-Thr (residue 25) are recognized by anti-S and -s. Carboxymethylation, performic acid, hydrogen peroxide and cyanogen bromide treatment destroy the S antigen, but have no effect on the s receptor. This suggests that the S antigen is determined by a methionyl-residue.

Signal transduction by glycophorin A: role of extracellular and cytoplasmic domains in a modulatable process

Binding of ligands to the extracellular region of the erythrocyte transmembrane protein glycophorin A induces a decrease in membrane deformability. Since the property of membrane deformability is regulated by the skeletal proteins on the cytoplasmic side of the membrane, this suggests that ligand binding may initiate a transmembrane signal. To further study this process, we examined which domains of the extracellular region of glycophorin are involved in signal transduction and whether the cytoplasmic domain of the molecule is necessary for transmitting the signal. Using the ektacytometer, we compared the effect on deformability of four monoclonal antibodies that detect different epitopes on glycophorin A. We found that 9A3 (which recognized the amino terminus of glycophorin) caused a 5.8-fold increase in rigidity, R-10 and 10F7 (which recognized epitopes in the mid-region of the extracellular domain) caused a 10.8-fold increase in rigidity and B14 (which binds to glycophorin close to the membrane) caused a 18-fold increase in rigidity. Further, a direct relationship was observed between the degree of antibody-induced rigidity and the amount of glycophorin A that became associated with the skeletal proteins in a Triton shell assay. In Miltenberger V erythrocytes, which contain a hybrid sialoglycoprotein with no cytoplasmic domain, antibody binding did not induce an increase in rigidity. These results imply that glycophorin A is capable of a modulatable form of transmembrane signaling that is determined by the extracellular domain to which the ligand binds, and the cytoplasmic domain of glycophorin A is crucial for this process.

Anti-Wrb, and other autoantibodies responsible for positive direct antiglobulin tests in 150 individuals

Eluates from the red blood cells (and sera whenever free autoantibody was present) of 150 individuals with positive direct antiglobulin tests, have been studied for antibody specificity. Of 87 patients with AIHA, 64 had autoantibodies reacting with all red cell samples including Rhnu11. Of these 64 anti-d1 autoantibodies, two were, and 32 contained, auto-anti-Wrb. Of 33 patients being treated with alphamethyldopa, who had developed positive direct antiglobulin tests, 23 had anti-d1 autoantibodies four of which contained auto-anti-Wrb. Of 30 haematologically normal donors with positive direct antiglobulin tests, 23 had anti-d1 autoantibodies, two of which were, and six of which contained, auto-anti-Wrb. The full specificities of autoantibodies, other than anti-Wrb and anti-d1, in the 150 patients are described, as are the natures of the protein red cell coatings that caused the positive direct antiglobulin tests. The presence of free serum autoantibody as a correlate of the three clinical conditions is reported. Several observations on auto-anti-Wrb are documented. The antibody can cause gross red cell destruction in vivo, but can be benign on other occasions; it occurs with approximately the same frequency in AIHA patients and "normal" donors with positive direct antiglobulin tests, but in fewer patients with alphamethydopa induced positive direct antiglobulin tests; it does not activate complement in vivo; and finally it may eventually provide a clue to the aetiology of AIHA.

Comparison of alkal-labile oligosaccharide chains of M and N blood-group glycopeptides from human erythrocyte membrane

Alkali-borohydride degradation of M or N blood-group active, tryptic glycopeptides and glycoproteins was performed under conditions giving the reduced oligosaccharides in a yield significantly improved over that reported earlier. Degradation of desialosylated glycoproteins yielded beta-D-Galp-(1 leads to 3)-D-GalNAcol, D-GalNA-col, and Galol in a ratio of approximately 30:1:1. GalNAc was shown to be alpha-D-linked to the polypeptide chain. Degradation of the glycopeptides gave the tetrasaccharide, NeuAc-(2 leads to 3)-beta-D-Galp-(leads to 3)-[NeuAc-(2 leads to 6)]-D-GalNAcol, and two trisaccharides, NeuAc-(2 leads to 3)-beta-D-Galp-(1 leads to 3)-D-GalNAcol and beta-D-Galp-(1 leads to 3)-[NeuAc-(2 leads to 6)]-D-GalNAcol, in a molar ratio of approximately 8:3:1. These oligosaccharides were accompanied by minor amounts of unidentified compounds showing identical electrophoretic mobility when derived from M and N glycopeptides. During isolation of the reduced oligosaccharides, the release of sialic acid did not exceed 5.5%, indicating that only a part of the trisaccharide portion might have arisen as a result of desialosylation of the tetrasaccharide. No differences between the degradation products derived from M and N glycoproteins were found, and the presence of significant amounts of larger, alkali-labile oligosaccharides was not observed.

Structural analysis of a membrane glycoprotein: glycophorin A

Glycophorin A is the major sialoglycoprotein of the human erythrocyte membrane. Structural studies indicate that this molecule is made up of 3 domains composed of 2 hydrophilic segments which are separated by a region of 22 nonpolar amino acids. The N-terminal half of the molecule contains all the carbohydrate associated with this protein. Glycophorin A forms high-molecular-weight complexes which can be dissociated only under certain conditions. The site of subunit interaction is located within the hydrophobic segment, which serves both to mediate protein-protein and protein-lipid interactions within the bilayer membrane. Glycophorin A spans the membrane presumably as a dimeric complex with the carboxyterminal ends extending into the cytoplasm of the red cell. The transmembrane nature of the polypeptide chains finds strong support from the use of specific antibody-ferritin conjugates applied to thin sections of fixed and frozen intact cells. Preliminary information on the analysis of human red cell variants which may lack some or all of the sialoglycopeptides are consistent with the presence in normal cells of a second sialoglycoprotein, provisionally labeled glycophorin B.

A new human erythrocyte variant (Ph) containing an abnormal membrane sialoglycoprotein

1. A new human erythrocyte variant (Ph) is described. The variant contains an unusual sialic acid-rich glycoprotein in addition to the blood-group-MN([unk])- and blood-group-Ss(delta)-active sialoglycoproteins found in normal erythrocytes. 2. The unusual component Ph has an apparent mol.wt. of 32000 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The Ph component is not degraded during trypsin treatment of intact erythrocytes. 3. The Ph component was labelled by lacto-peroxidase-mediated radioiodination of intact erythrocytes and was found to be present in amounts approximately equimolar to alpha-sialoglycoprotein in the variant erythrocytes. 4. The Ph component had receptors for the lectins from Maclura aurantiaca (osage orange) and Triticum vulgaris (wheat-germ), but lacked a receptor for the Phaseolus vulgaris (red kidney bean) lectin, suggesting that it carries only O-linked oligosaccharides. 5. The presence of the Ph component in these erythrocytes does not correspond to any of the known blood-group-MNSs-related antigens examined. 6. We suggest that this component may be a hybrid polypeptide containing the N-terminal portion derived from normal delta-sialoglycoprotein, and the C-terminal portion from normal alpha-sialoglycoprotein, in a manner similar to the anti-Lepore haemoglobin.

Studies on the role of red blood cell glycoproteins as receptors for invasion by Plasmodium falciparum merozoites

The mechanism of invasion of human red blood cells by Plasmodium falciparum merozoites has been studied by several indirect methods. Red blood cells of the S+s+U+ and S-s-U- blood group phenotypes were trypsin treated and their susceptibility to invasion measured. Trypsin-treated S+s+U+ cells lack the portion of glycophorin A which bears the MN blood group determinants but possess glycophorin B, whereas trypsin-treated S-s-U- cells lack both the glycophorin A MN determinants and the glycophorin B molecule. Since the treated S-s-U- cells showed an even greater loss in susceptibility to invasion that the treated S+s+U+ cells, we conclude that glycophorin B does have a role In merozoite recognition, although it appears less important than glycophorin A. Attempts to decrease invasion by pretreatment with glycosidases were unsuccessful, except for the previously reported effect of neuraminidase. N-acetyl-D-glucosamine decreases the appearance of ring-stage parasites after in vitro reinvasion of P. falciparum. However, the persistence of intact and lysed schizont-infected cells when N-acetyl-D-glucosamine was present, several hours after disappearance of these cells from control cultures, leads us to conclude that this sugar has a deleterious effect on terminal stages of parasite maturation. It is therefore not possible to conclude that N-acetyl-D-glucosamine inhibits merozoite attachment and reinvasion specifically by competition for the receptor.

Studies on the membrane glycoprotein defect of En(a-) erythrocytes. III. N-terminal amino acids of sialoglycoproteins from normal and En(a-) red cells

Sodium dodecylsulphate polyacrylamide gel electrophoretic methods and quantitative analyses of the N-terminal amino acids were applied to the sialoglycoprotein mixture and glycoprotein fractions from normal erythrocyte membranes, as well as preparations from red cells of individuals belonging to the English and Finnish En(a-) families. The data confirm the observation by alternative methods that SS cells exhibit a higher Ss glycoprotein content than ss erythrocytes. The results of end-group analyses suggest that the N-terminal amino acids serine and leucine represent the structures differentiating the MN and the 'M' and 'N' antigens on the MN and Ss glycoproteins respectively. Data from peptide sequence analyses confirm that the glycine/glutamic acid polymorphism at the fifth position of the MN glycoprotein's peptide chain is closely or absolutely linked with the serine/leucine polymorphism at its N-terminal position. As normal (EnaEna) red cells exhibiting 'M' antigenic properties have not been detected, the hypothesis is proposed that the Ss glycoprotein of English En(a-) erythrocytes possesses an MN-Ss hybrid polypeptide chain analogous to those of the delta-beta Lepore haemoglobins.