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M J Telen

Publications and source records attributed to M J Telen.

At least 55 records · Page 3Linked to original sources
PubMed1992

Isolation of the JMH antigen on a novel phosphatidylinositol-linked human membrane protein.

JMH is a high-frequency human erythrocyte blood group antigen. Previous work has shown that JMH is absent from complement-sensitive erythrocytes of patients with paroxysmal nocturnal hemoglobinuria (PNH); such cells have a broad defect in expression of phosphatidylinositol (PI)-linked proteins. Using both human JMH antisera and a JMH-like murine monoclonal antibody, we have identified a 76-Kd membrane protein present in JMH-positive but not JMH-negative erythrocytes. A similar 76-Kd JMH protein was also identified on a human lymphoid T-cell line, HSB-2. Using PI-specific phospholipase C, a small amount of JMH antigen could be cleaved from intact erythrocytes and immunoprecipitated from the supernate of treated erythrocytes, thus confirming that the protein bearing the JMH antigen is anchored by a PI-linkage to the erythrocyte membrane. This protein was further shown not to be identical to decay accelerating factor (70 Kd), a previously identified PI-anchored protein of somewhat similar molecular weight.

Blood Group Antigens↗
PubMed1991

Molecular basis for elliptocytosis associated with glycophorin C and D deficiency in the Leach phenotype.

Glycophorin C (GPC) and glycophorin D (GPD) are highly glycosylated integral membrane proteins of human erythrocytes encoded by the same gene and associated with expression of Gerbich blood group system antigens. GPC/D deficiency (the Leach phenotype) is a rare condition usually found after identification of Gerbich blood group system antibodies in persons undergoing prenatal or pretransfusion evaluation. In all cases, the Leach phenotype has been associated with elliptocytosis. Characterization of the molecular basis of this phenotype in three previously uninvestigated families has shown that the most common genetic basis of GPC/D deficiency is deletion of exons 3 and 4 of the GPC gene. However, in one family, the Leach phenotype appeared due to a deletion of one nucleotide in exon 3, causing a frameshift mutation in the messenger RNA and premature generation of a stop codon. The GPC and GPD protein sequences are therefore interrupted in the extracellular domain and probably intracellularly degraded.

Amino Acid Sequence↗
PubMed1991

Identification of human erythrocyte blood group antigens on the C3b/C4b receptor.

The Knops/McCoy (Kn/McC) human erythrocyte blood group system belongs to the category of blood group Ag that generate so-called "high titer low avidity" antibodies in immunized transfusion recipients. Screening of red cells lacking certain high titer low avidity Ag demonstrated markedly diminished CR1 expression on McC(d-) and Kn/McC "null" (Kn(a-)McC(a-b-c-d-e-f-] erythrocytes. Additional testing by other methods confirmed these data, and biochemical assays demonstrated no detectable immunoreactive CR1 protein in membranes from Kn/McC null red cells. Human antisera to various Kn/McC Ag were then used to demonstrate that many of these antisera could be used to isolate a protein of identical m.w. to that isolated from the same cells using murine mAb CR1 antisera. Finally, protein isolated by using murine mAb anti-CR1 reacted specifically with anti-Kn/McC antibodies, demonstrating the identity of the Kn/McC and CR1 proteins. Thus, CR1 protein bears the human erythrocyte Kn/McC blood group Ag.

Antibodies, Monoclonal↗
PubMed1991

Phosphatidylinositol-glycan linked proteins of the erythrocyte membrane.

The human erythrocyte bears a number of proteins anchored to the outer membrane surface via a phosphatidylinositol-glycan linkage. This class of proteins includes several complement regulatory proteins (including decay-accelerating factor, CD59 antigen (protectin), and C8 binding protein) as well as several enzymes and at least one protein important in cell-cell interaction. In addition, a number of blood group antigens have been identified to reside on proteins with phosphatidylinositol anchors. One blood group (Cromer) resides on DAF. Study of variants in this blood group system has led to interesting information about the function and expression of this protein. Several other blood groups, such as JMH and Holley/Gregory, appear to reside on as yet unidentified phosphatidylinositol-linked proteins. In paroxysmal nocturnal haemoglobinuria, a variable proportion of red cells fail to express or express weakly all phosphatidylinositol-linked proteins. The origin of this deficiency is now being worked out. In addition, individuals with inherited deficiency of DAF or CD59 (protectin) have been identified. Only the latter deficiency leads to a PNH-like syndrome.

Antigens↗
PubMed1991

Captopril-enhanced binding of PlA1 (HPA-1a) antibodies in posttransfusion purpura.

A case of posttransfusion purpura is reported in a 90-year-old patient whose PlA1 antibody (anti-HPA-1a) was found to bind better to HPA-1a in the presence of captopril, a drug the patient had taken. Initially, IgG antibodies were found in the serum that reacted with normal platelets, but the binding of the antibody was increased in vitro by captopril, which suggested that captopril was responsible for the thrombocytopenia. However, in vitro studies demonstrated that the patient's platelets were negative for HPA-1a and that anti-HPA-1a was present in the serum, both of which findings were consistent with the diagnosis of posttransfusion purpura. The binding of this antibody was enhanced 50 percent by captopril in vitro, and increased binding in the presence of captopril did not occur when the anti-HPA-1a was removed. Similar results were obtained with serum containing anti-HPA-1a from another patient with posttransfusion purpura. Thus, captopril may increase the binding of anti-HPA-1a and confuse the determination of the cause of acute thrombocytopenia.

Aged↗
PubMed1991

An auto-anti-M causing hemolysis in vitro.

A 64-year-old white man, who had never received a transfusion, was found to have anti-M in his serum. The antibody agglutinated all M+ red cells in room-temperature tests. When the ionic strength of the test milieu was reduced by use of an additive solution and the tests were incubated at 37 degrees C, the antibody hemolyzed M + N- but not M+N+ red cells. All M+ red cells reacted in indirect antiglobulin tests using polyspecific antiglobulin reagents when such tests followed an initial incubation at room temperature. When red cells and the patient's serum were warmed to 37 degrees C before being mixed, no antibody activity was demonstrable. The antibody was adsorbed to exhaustion onto M+N- and M+N+ red cells (including the patient's own), and its activity was destroyed by dithiothreitol. There was no evidence of in vivo red cell destruction by the autoantibody. No previously reported example of anti-M has been shown to activate complement in conventional in vitro tests. This example was extraordinary in that it caused sufficient complement activation to present as an in vitro hemolysin.

Antibody Specificity↗
PubMed1991

Dr(a-) polymorphism of decay accelerating factor. Biochemical, functional, and molecular characterization and production of allele-specific transfectants.

The Dra antigen belongs to the Cromer-related blood group system, a series of antigens on decay accelerating factor (DAF), a glycosyl-phosphatidylinositol-anchored membrane protein that protects host cells from complement-mediated damage. We studied the rare inherited Dr(a-) phenotype to ascertain the associated biochemical and functional changes in DAF and to characterize the basis for this polymorphism. Radioimmunoassay assay and flow cytometric analysis of Dr(a-) erythrocytes demonstrated 40% of normal surface expression of DAF but normal levels of several other glycosyl-phosphatidylinositol-anchored proteins, distinguishing this phenotype from that of paroxysmal nocturnal hemoglobinuria. Western blots confirmed this reduced DAF expression and indicated a slightly faster mobility of the molecule on SDS-PAGE. Despite the reduced DAF expression, Dr(a-) erythrocytes functioned normally in the complement lysis sensitivity assay. Utilization of the polymerase chain reaction to amplify mononuclear cell genomic DNA from three unrelated Dr(a-) individuals demonstrated that a point mutation underlies the Dr(a-) phenotype: a C to T change in nucleotide 649 resulting in a serine165 to leucine change. This defines the Drb allele of DAF, which can be distinguished from Dra by a Taq I restriction fragment length polymorphism. We created transfected Chinese hamster ovary cell lines expressing either the Dra or the Drb allelic form of DAF. These allele-specific transfectants were tested by inhibition of hemagglutination or flow cytometry and confirmed the specificity of anti-Dra alloantisera. The allele-specific transfectants could form the basis of a new serological approach to immunohematology.

Alleles↗
PubMed1991

Phosphatidylinositol-linked red blood cell membrane proteins and blood group antigens.

A new class of membrane proteins has recently been described. Unlike integral membrane proteins, which traverse the membrane with one or more hydrophobic peptide domains, the peptide domains of these more newly described proteins are entirely extracellular and are anchored to the cell membrane via a phosphatidylinositol-glycan (GPI) anchor. Erythrocyte membrane proteins of this class include proteins with diverse functions; several, however, are complement regulatory proteins. Moreover, it is the lack of expression of GPI-anchored proteins that is responsible for manifestations of the acquired hematologic disease paroxysmal nocturnal hemoglobinuria. Recently, several investigators have also demonstrated that a number of erythrocyte blood group antigens reside on this class of proteins. These antigens include those of the Cromer blood group, JMH, Holley/Gregory, Cartwright, and Dombrock. The biochemical basis for the Cromer, JMH, and Holley/Gregory antigens have so far been partly delineated.

Journal Article↗
PubMed1990

Relationship of the human erythrocyte Wrb antigen to an interaction between glycophorin A and band 3.

The Wrb antigen is a high-frequency human erythrocyte antigen invariably absent from En (a-) erythrocytes, which lack glycophorin A. However, glycophorin A from En (a+) Wr (a+b-) red cells has an amino acid sequence identical to that of glycophorin A from Wr (b+) erythrocytes. Evidence has suggested that the Wrb antigen may require the interaction of glycophorin A with either a lipid moiety or with another erythrocyte-integral membrane protein, band 3. We have investigated the role of band 3 in Wrb expression using murine monoclonal antibodies (MoAbs) with Wrb specificity. These antibodies reacted by radioimmunoassay (RIA) only with cells expressing both glycophorin A and band 3. In immunoprecipitation studies, Wrb antibodies immunoprecipitated both band 3 and glycophorin A, while antibodies specific for band 3 or glycophorin precipitated only the protein with which they were reactive. These data strongly suggest that band 3 is the other membrane component necessary for expression of Wrb and that band 3 and glycophorin A are closely associated in the erythrocyte membrane.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1990

Evidence that several high-frequency human blood group antigens reside on phosphatidylinositol-linked erythrocyte membrane proteins.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder associated with absence of expression of phosphatidylinositol (PI)-linked membrane proteins from circulating hematopoietic cells of multiple lineages. Recent work demonstrated that decay accelerating factor, one such PI-linked protein, bears the Cromer-related blood group antigens. This study demonstrated that other high incidence antigens, including Cartwright (Yta/Ytb), Holley-Gregory (Hy/Gya), John Milton Hagen (JMH), and Dombrock (Doa/Dob), are absent from the complement-sensitive (PNH III) erythrocytes of patients with PNH. The relatively normal, complement-insensitive erythrocytes from the same patients express these antigens normally. Therefore, these antigens most likely reside on PI-linked proteins absent from PNH III, but not PNH I, erythrocytes.

Antibodies↗
PubMed1990

Relationship of Inb antigen to other antigens on In(Lu)-related p80.

The Ina and Inb antigens have recently been added to the list of diverse erythrocyte blood group antigens whose expression is down-regulated by the In(Lu) gene. Evidence has been provided that these antigens constitute polymorphisms of an erythrocyte glycoprotein previously defined by its reactivity with murine monoclonal antibodies, such as A3D8, and designated In(Lu)-related p80. This study has now confirmed the assignment of the Inb antigen to p80 and has further studied the relationship of the Inb epitope to other p80 epitopes recognized by both monoclonal antibodies as well as polyclonal antiserum produced against purified erythrocyte p80.

Antigens, CD↗
PubMed1990

A case report: IgG autoanti-N as a cause of severe autoimmune hemolytic anemia.

A 21-year-old white worn was referred for evaluation of hemolytic anemia after a 9-day history of marked hemoglobinuria, jaundice, and weakness. The patient's hematocrit was 18%, despite at least eight transfusions over the previous week, and the reticulocyte count was < 1%. Serologic evaluation revealed a weakly positive direct antiglobulin test with anti-C3 only The serum contained cold and warm-reacting anti-N Dithiothreitol had no effect on either the cold- or the warm-reacting anti-N activity, and radioimmunoassay with monoclonal anti-IgG was strongly positive, indicating that both the cold- and the warm-reacting anti-N reactivity resided in the IgG fraction. The patient was treated with N - 'N' + red cell transfusions, prednisone, and azathioprine and gradually became transfusion independent. Postrecovery typing revealed her red cells to be M+N+S+s+. This constitutes the third case of autoimmune hemolytic anemia associated with IgG autoanti-N. The marked hemoglobinuria and reticulocytopenia are unique features of this case.

Journal Article↗
PubMed1990

HIV-associated autoimmune hemolytic anemia: report of a case and review of the literature.

While anemia and a positive direct anti-globulin test are each frequently observed in the clinical syndrome of human immunodeficiency virus (HIV) infection, autoimmune hemolytic anemia has rarely been reported in this setting. A case of severe warm autoimmune hemolytic anemia (AIHA) with reticulocytopenia in a patient with AIDS-related complex is reported. Laboratory and clinical findings of severe hemolysis were present, including anhaptoglobinemia, microspherocytosis, splenomegaly, and transfusion dependence. Azidothymidine (AZT) therapy may have exacerbated this patient's anemia. Splenectomy produced a delayed but complete remission of the AIHA despite continuation of AZT therapy. Review of other reports of positive direct antiglobulin tests and autoimmune hemolytic anemia in patients with HIV infections suggests that autoantibodies may be a significant cause of anemia in this population and that the frequent lack of reticulocytosis, despite bone marrow erythroid hyperplasia, may lead to the underdiagnosis of AIHA in HIV-infected patients.

AIDS-Related Complex↗
PubMed1989

Monoclonal antibodies against the CD44 [In(Lu)-related p80], and Pgp-1 antigens in man recognize the Hermes class of lymphocyte homing receptors.

An 85- to 95 kDa class of lymphocyte surface molecules, defined in man by antibodies of the Hermes series, is involved in lymphocyte binding to high endothelial venules and is likely of central importance in the process of lymphocyte homing. In this report, we have examined the relationship between these Hermes-defined "homing-receptors" and two other 80 to 95 kDa lymphocyte surface molecules that have been extensively studied--CD44 [In(Lu)-related p80] defined by mAb A1G3 and A3D8, and Pgp-1 defined by antibody IM7. Our findings indicate that, in man, similar or identical glycoprotein(s) are recognized by these independently and diversely obtained antibodies. All antibodies showed identical immunohistologic patterns of reactivity on a variety of lymphoid and nonlymphoid human tissues, and demonstrated similar bands on Western blots of both crude tonsil lymphocyte lysates and highly purified Hermes-1 Ag preparations. Similarly, purified CD44/p80 Ag from RBC and human serum bound Hermes-1. Preclearing of tonsil lysates with the Hermes-1 antibody removed antigenic activity for all antibodies. Cross-blocking experiments demonstrated that A3D8, IM7 (anti-Pgp-1), and Hermes-2 antibodies recognize overlapping epitopes. Finally, expression of the epitopes defined by the Hermes-1, Hermes-3, H2-7, and H3-61 antibodies on RBC was shown to be regulated by the In(Lu) gene. These findings unify several different lines of investigation, and suggest the possibility that the CD44/Pgp-1/Hermes class of molecules may serve as cell-cell or cell-substrate adhesion/recognition elements for both hematolymphoid and non-hematolymphoid cell types.

Animals↗
PubMed1989

CD44--a molecule involved in leukocyte adherence and T-cell activation.

The study of cell surface molecules that are involved in interactions between immune and non-hematopoietic cells in various microenvironments is currently an area of great interest. One molecule that appears to be involved in multiple steps of normal immune cell function is now called CD44 and has been known previously as Pgp-1, In(Lu)-related p80, Hermes, ECM-III and HUTCH-I. Within the past year, the co-identity of all of these independently discovered molecules has become apparent, and the role of the CD44 molecule in T-cell activation has been discovered. In this review, Barton Haynes and his colleagues bring together numerous divergent lines of investigation on the CD44 molecule, review the many functional roles attributed to it, and present a unifying view of how, with numerous ligands, it may participate in several areas of normal immune cell function.

Amino Acid Sequence↗
PubMed1989

The Inab phenotype: characterization of the membrane protein and complement regulatory defect.

Recent demonstration that Cromer-related human blood group antigens reside on decay-accelerating factor (DAF) has led to identification of an apparent null phenotype (Inab) for erythrocyte DAF. This study examined expression of other phosphatidylinositol (PI)-anchored proteins by Inab erythrocytes and showed that the PI-linked membrane proteins acetylcholinesterase (AchE) and lymphocyte function-associated antigen-3 (LFA-3) are normally expressed by these cells. Furthermore, studies of the complement sensitivity of Inab RBCs demonstrated them to be abnormally complement sensitive, with an apparent defect in downregulation of C3 convertase activity. Thus, the Inab phenotype appears to represent an instance of hereditary erythrocyte DAF deficiency whose mechanism differs from that of paroxysmal nocturnal hemoglobinuria (PNH) and which is unassociated with clinically evident hemolytic disease.

Acetylcholinesterase↗
PubMed1989

Characterization of the serum In(Lu)-related antigen: identification of a serum protein related to erythrocyte p80.

The In(Lu) gene has been shown previously to downregulate expression by erythrocytes and by a subset of leukocytes of an 80-Kd protein antigen defined by monoclonal antibody (MoAb) A3D8. A3D8 antibody has also been shown by inhibition studies to recognize a serum antigen; this serum antigen is present in reduced amount in serum from In(Lu) donors. The present study demonstrates that the serum antigen recognized by A3D8 antibody also resides on a protein similar in size to the protein present in erythrocyte membranes. Studies using chromatographically purified protein have further shown that this antigen shares many epitopes with that present in RBCs and is therefore likely to be extremely homologous or identical to the erythrocyte In(Lu)-related p80.

Animals↗