Biomedical subjects

L A Rubin

Publications and source records attributed to L A Rubin.

At least 55 records · Page 3Linked to original sources

PubMed1989

Linkage studies of the Wiskott-Aldrich syndrome: polymorphisms at TIMP and the X chromosome centromere are informative markers for genetic prediction.

Eleven families segregating for the X-linked recessive immune deficiency disorder, Wiskott-Aldrich syndrome (WAS), were studied by linkage analysis with an alpha satellite DNA probe, pBamX-7, which detects polymorphisms at the X chromosome centromere, locus DXZ1, as well as three other polymorphic markers defining loci on the proximal short arm of the X chromosome. Linkage has been established between WAS and DXZ1 (zeta (theta) = 7.08 at theta = 0.03) and WAS and the TIMP gene locus (zeta (theta) = 5.09 at theta = 0.0). We have also confirmed close linkage between DXZ1 and two marker loci, DXS14 and DXS7, previously shown to be linked to the WAS locus. The probe pBamX-7 detected allelic variation in all females tested, reflecting the high frequency of polymorphism at the centromere. One WAS carrier revealed a recombination between WAS and both marker loci DXZ1 and DXS14, indicating that WAS does not map between these loci. In conjunction with previous data from genetic mapping studies of WAS, these results confirm the pericentromeric Xp localization of WAS and demonstrate the usefulness of alpha satellite DNA probes as tools for genetic prediction in WAS as well as other pericentric X-linked diseases.

Centromere↗

PubMed1989

X-chromosome inactivation in the Wiskott-Aldrich syndrome: a marker for detection of the carrier state and identification of cell lineages expressing the gene defect.

Recently developed techniques for the direct analysis of DNA have made possible the determination of patterns of cellular X-chromosome inactivation. These techniques provide a potential method for carrier detection for several X-linked human disorders in which obligate carriers show nonrandom X inactivation. By using restriction fragment length polymorphic (RFLP) gene-specific probes in conjunction with methylation-sensitive enzymes, we have characterized the patterns of X-chromosome inactivation in cell subsets from females belonging to 10 kindreds segregating for the X-linked immune deficiency disorder Wiskott-Aldrich syndrome (WAS). We show that selective inactivation of the X chromosome distinguishes obligate WAS carriers from noncarrier females and constitutes a valuable marker of the WAS carrier state. Selective inactivation phenomena were observed in the monocytes and T and B lymphocytes of obligate carriers, implying that the WAS gene defect is expressed in each of these cellular lineages. In conjunction with the use of linked DNA markers, RFLP-methylation analysis should render carrier detection feasible for the majority of females from WAS families. The results of such analyses also provide an initial step toward identifying the cellular level and molecular basis for WAS.

DNA Probes↗

PubMed1989

Altered expression of leucocyte sialoglycoprotein in Wiskott-Aldrich syndrome is associated with a specific defect in O-glycosylation.

The Wiskott-Aldrich syndrome (WAS) is an X-linked immune deficiency disorder characterized clinically by both lymphocyte and platelet dysfunction. Studies of WAS T lymphocytes have revealed deficient or defective cell surface expression of the highly O-glycosylated leucocyte sialoglycoprotein CD43. To further elucidate the basis for, and functional relevance of, CD43 modifications on WAS lymphocytes, we have studied lymphocytes from two WAS patients with regard to membrane glycoprotein profile and mitogen-induced proliferative responses. CD43 was found to be either absent or altered in size on peripheral blood lymphocytes and lectin-stimulated T cells from both patients. Compared with control cells, the WAS lymphocytes displayed reduced, but measurable proliferative responses to lectins and neuraminidase/galactose oxidase, and virtually no response to periodate, a mitogenic agent which targets sialic acid residues on membrane glycoproteins such as CD43. Analysis of activities of three glycosyltransferases involved in O-glycosylation revealed marked reduction in the level of activity of UDP-N-acetylglucosamine: Gal beta 1-3GalNAc-R beta-1,6-N-acetylglucosamine (beta-1,6-GlcNAc) transferase in one WAS patient and no detectable activity of this enzyme in a second. beta-1,6-GlcNAc transferase activity has recently been shown to increase during T cell activation coincident with changes in the O-linked glycans on CD43. A selective reduction of this glycosyltransferase in WAS lymphocytes suggests that O-linked oligosaccharides may be important to the structure of membrane glycoproteins involved in lymphocyte activation.

Cell Division↗

PubMed1988

Elevated serum levels of soluble Tac peptide in adult T-cell leukemia: correlation with clinical status during chemotherapy.

Adult T-cell leukemia associated with human T-cell leukemia virus type I (HTLV-I) is characterized by a clonal expansion of a CD4-positive subset of T lymphocytes that constitutively express high numbers of interleukin-2 receptors and that frequently infiltrate the skin; osteolytic bone lesions, and hypercalcemia. Using an enzyme-linked immunosorbent assay (ELISA) test, we measured the level of soluble Tac peptide, one chain of the human interleukin-2 receptor, in the serum of 50 patients with adult T-cell leukemia (38 Japanese and 12 American patients), 8 patients with other hematologic malignancies, 8 asymptomatic HTLV-I-antibody-positive carriers, and 17 normal controls. The serum level of soluble Tac peptide (geometric mean U/mL, 95% CI) was elevated at presentation in all patients with adult T-cell leukemia (16,461; 819 to 330,896) when compared with normal controls (238; 112 to 502), patients with other hematologic malignancies (1302; 475 to 3569), and healthy HTLV-I antibody-positive carriers (490; 115 to 2086). The highest levels were seen in patients (n = 33) with acute (32,154; 2587 to 399,598) compared with chronic (5464; 661 to 45,156) disease (n = 14). Serum levels of Tac peptide also tended to be more elevated in patients with adult T-cell leukemia with hypercalcemia (32,072; 2461 to 417,908) compared with normocalcemic patients (13,885; 496 to 388,436). Serial measurements of soluble Tac peptide levels in serum were done in four patients with adult T-cell leukemia during chemotherapy and the levels reflected disease activity. These observations suggest that the measurement of soluble Tac peptide levels in patients with adult T-cell leukemia is useful as a noninvasive measure of tumor burden and will help in the diagnosis of the disease and management of these patients.

Acute Disease↗

PubMed1988

Elevated soluble interleukin-2 receptor levels in the sera and synovial fluids of patients with rheumatoid arthritis.

In a previous study, we used an enzyme-linked immunosorbent assay to measure soluble human interleukin-2 receptors (IL-2R), and found that when activated lymphocytes produce cell-associated IL-2R, they also release a soluble form of IL-2R into culture supernatants in vitro. Soluble IL-2R have also been detected circulating in vivo at low levels in the serum of healthy individuals, and at abnormal levels in a variety of diseases, particularly those where immune dysfunction is thought to play an important role. We therefore evaluated serum IL-2R levels in 77 patients with rheumatoid arthritis (RA), and compared them with levels in 46 age-matched healthy controls. Nineteen additional RA patients with concurrently obtained sera and synovial fluid (SF) samples were compared with 14 patients with osteoarthritis of the knee or hip. The serum IL-2R levels were significantly elevated in RA patients, compared with the control groups (P less than 0.0001). Serum IL-2R levels in the RA patients did not correlate with disease activity as determined by a variety of clinical and laboratory parameters. RA SF IL-2R levels were significantly higher than corresponding RA serum IL-2R levels (P = 0.0001). No such difference was noted in the osteoarthritis group, where serum and SF IL-2R levels were comparable with serum levels in healthy controls. These findings support the hypothesis that in vivo lymphocyte activation plays an important role in RA; moreover, soluble IL-2R measurement in serum and SF may be a very useful way to identify patients at risk for, or manifesting, a chronic immune-mediated inflammatory arthropathy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1987

Reconstitution of a functional interleukin 2 receptor in a nonlymphoid cell.

The maintenance of T lymphocytes which are important effectors of immune responses requires the T cell growth factor, interleukin 2 (IL-2). The binding of IL-2 to specific cell-surface receptors (IL-2R) has previously been shown to be essential to the growth and proliferation of activated lymphocytes. A human IL-2R cDNA sequence, placed under the control of the SV40 transcriptional promoter and enhancer, has been transfected into murine L cells. Single cell analysis by autoradiography was used to show that fibroblastic L cells, stably expressing human IL-2R, respond to stimulation with IL-2 by DNA synthesis and proliferation. This response is specifically blocked by the addition of an anti-IL-2R monoclonal antibody, anti-Tac, as previously reported. Neither nonspecific antisera nor 7G7/B6, an anti-IL-2R monoclonal antibody which does not interfere with IL-2 binding to its receptor, had any effect on this response. The induction of DNA synthesis by IL-2 is both rapid and dose-dependent. The ability of IL-2 to stimulate these transfected L cells to proliferate demonstrates that a lymphoid environment is not required for the functional interaction between IL-2 and its receptor, and provides a unique model system for the investigation of the molecular basis for the cellular events mediated by IL-2.

Animals↗

PubMed1987

In vivo administration of purified human interleukin-2 to patients with cancer: development of interleukin-2 receptor positive cells and circulating soluble interleukin-2 receptors following interleukin-2 administration.

Recent studies have demonstrated efficacy of immunotherapies including interleukin-2 (IL-2) in the treatment of malignancies in rodents and humans. High levels of IL-2 receptor-positive cells were found in the peripheral blood of patients receiving recombinant IL-2 in these Phase I clinical trials. This was demonstrated both in patients receiving i.v. IL-2 who had detectable circulating levels of IL-2 as well as in patients receiving i.p. IL-2 who did not. Up to 100% of the anti-Tac binding could be inhibited by preincubation with IL-2 indicating that this was indeed an IL-2 receptor that was identified. Two-color experiments demonstrated that few Leu 2-positive cells (less than 5-10%) but over 30% of the Leu 3-positive cells bore Tac antigen. Most of the M3-positive monocytes were Tac positive (83.7%) and negative for other T-cell (Leu-4) and nonspecific murine markers (Lyt-2 and Thy 1.2). Although normal individuals had a mean of only 186 units/ml (range, 83-335 units/ml) of soluble IL-2 receptor, patients receiving IL-2 had as much as 20,000 units/ml of soluble IL-2 receptor line in their serum. The physiological role of the IL-2 receptor identified on the cell surface of Leu 3 and M3-positive cells as well as in the serum is unclear. Soluble IL-2 receptors appeared in the circulation early following IL-2 administration, approximately 1 week prior to the detection of circulating IL-2 receptor-bearing cells. Further studies will be needed to assess the role of IL-2 in monocyte function, the precise function of IL-2 receptor-bearing Leu 3-positive cells, and the relationship of these findings to the toxicity and success of this immunotherapy in humans.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1987

Soluble interleukin 2 receptors are elevated in patients with AIDS or at risk of developing AIDS.

Utilizing an enzyme-linked immunosorbent assay, we detected elevated serum levels of soluble interleukin 2 receptors (SIL-2R) in 73% of patients with acquired immunodeficiency syndrome (AIDS), 80% of AIDS-related complex patients, 78% of anti-HIV-positive lymphadenopathy syndrome patients, 85% of HIV-antibody-positive hemophiliacs, and 80% of anti-HIV-positive asymptomatic homosexual males, iv drug abusers, and heterosexual contacts. Of the subjects with no demonstrable antibody to HIV, 29% of hemophiliacs, 12% of adult homosexual males and iv drug abusers, and none of the patients with lymphadenopathy had elevated SIL-2R. Overall, only 5 of 40 antibody-negative "high-risk" individuals had SIL-2R values greater than the reference interval whereas 108 of 138 antibody-positive individuals had elevated values (chi 2 = 57.85, P less than 0.001).

AIDS-Related Complex↗

PubMed1987

Soluble interleukin-2 receptor levels in patients with undifferentiated and lymphoblastic lymphomas: correlation with survival.

We have been able to detect soluble interleukin-2 receptors (IL-2R) in pretreatment sera from 80 patients with undifferentiated lymphoma (predominantly Burkitt's lymphoma) and lymphoblastic lymphoma. The demonstration of IL-2R in lymphoma-derived cell lines by immunoprecipitation and direct staining indicates that IL-2R is synthesized by the tumor cells. Comparisons were made with two other subject groups: 42 sarcoma patients and 17 normal individuals. The distribution of soluble IL-2R values for lymphoma patients (geometric mean, 1,132 U/mL) was significantly greater than that of sarcoma patients (geometric mean, 332 U/mL; P = .0001) or normal individuals (geometric mean, 238 U/mL; P = .0001). Patients with undifferentiated lymphoma stages B, C, and D had significantly higher soluble IL-2R values (geometric mean, 1,648 U/mL) than stages A and AR (geometric mean, 706 U/mL; P = .0001) or lymphoblastic lymphoma (geometric mean, 826 U/mL; P = .0002). Within the lymphoma group, the soluble IL-2R level was found to be the most significant prognostic indicator of disease-free interval and survival when compared with other previously recognized factors such as histology, stage, bone marrow involvement at presentation, lactic dehydrogenase (LDH), uric acid (UA), and age. No factor was significantly associated with response to therapy, ie, the initial achievement of complete remission (CR) status, although small numbers of patients with a partial response limit interpretation. Soluble IL-2R levels were measured serially in two patients and were found to be elevated at presentation or relapse and to decrease to normal levels during periods of disease remission. IL-2R appears to reflect tumor burden and may prove to be a useful and specific marker for lymphoid tumors.

Adolescent↗

PubMed1986

The released interleukin 2 receptor binds interleukin 2 efficiently.

The released interleukin 2 receptor (IL 2R) molecule was characterized in order to clarify its biochemical structure and to determine its functional capacity. Enzymatic digestions demonstrated that the released IL 2R, like the cell surface IL 2R, is a complex glycoprotein, modified by the addition of both N- and O-linked carbohydrates and sialic acid residues. It has a peptide backbone that is approximately 10 Kd smaller than that of its membrane-associated counterpart. Affinity chromatography demonstrated that released IL 2R from either an HTLV-I-positive T cell line (HUT-102) or PHA-activated normal peripheral lymphocytes binds efficiently to purified recombinant IL 2. Furthermore, the interaction between the growth factor and the released receptor does not appear to require any accessory molecules. These observations suggest a potentially significant role for the released IL 2R in the regulation of IL 2-dependent lymphocyte functions.

Carbohydrates↗

PubMed1986

A secreted form of the human interleukin 2 receptor encoded by an "anchor minus" cDNA.

The DNA sequence encoding all of the putative intracytoplasmic domain and most of the trans-membrane domain of the human IL 2 receptor was deleted from a full length receptor cDNA. After expression in mouse L cells, the resultant "anchor minus" cDNA was found to direct the synthesis of a secreted rather than membrane-associated form of the IL 2 receptor. The secreted receptor protein (44,000 to 46,000 Mr) retained the capacity to bind both IL 2 and the monoclonal anti-Tac antibody, as evidenced by retention on IL 2 and anti-Tac affinity columns, inhibition of [3H]-anti-Tac binding to HUT 102B2 cells, and partial inhibition of IL 2-induced CTLL proliferation. Removal of these domains from the IL 2 receptor did not alter the posttranslational processing or rate of export of the truncated receptor protein. These data confirm the proposed membrane orientation of the IL 2 receptor (NH2 terminus out, COOH terminus in) and underscore the anchoring function of this carboxy terminal receptor segment. The availability of such anchor minus receptor cDNA constructs may facilitate purification of large quantities of receptor protein for further analysis of receptor structure, valency, and localization of the IL 2 binding site(s).

Amino Acid Sequence↗

PubMed1986

An analysis of the cellular requirements for the production of soluble interleukin-2 receptors in vitro.

Following activation in vitro, peripheral blood mononuclear cells (PBMC) express cell-associated interleukin-2 receptors (IL-2R) and also release soluble IL-2R into culture supernatants. The present studies were undertaken to define which normal cells were responsible for the release of soluble IL-2R in vitro. Both cell-associated and soluble IL-2R were quantitatively measured with a "sandwich" enzyme-linked immunoassay employing two monoclonal antibodies. PBMC were separated into populations of surface immunoglobulin-negative cells (T cells and monocytes) and surface immunoglobulin-positive cells (B cells and monocytes), and the T-cell population was further separated into OKT4-positive (OKT4+) cells and OKT4-negative (OKT4-) cells. Following activation with phytohemagglutinin, pokeweed mitogen, and the monoclonal antibody OKT3, large amounts of soluble IL-2R were released by PBMC, unseparated T cells, OKT4+ T cells, and OKT4- T cells. The population containing B cells and monocytes made small but readily detectable amounts of soluble IL-2R when stimulated with these T-cell mitogens; likely the result of contaminating T cells in the population. However, when highly purified B cells were stimulated with Staphylococcus aureus Cowan and recombinant IL-2, they also released small amounts of soluble IL-2R. The release of soluble IL-2R by T cells appeared monocyte dependent when OKT3, but not phytohemagglutinin, was employed for activation, and monocytes themselves released no detectable IL-2R under the conditions employed. These studies define the cellular requirements for the release of soluble IL-2R in vitro and demonstrate that such receptors are released by B cells, T cells, and both OKT4+ and OKT4- T-cell subsets.

B-Lymphocytes↗

PubMed1986

The production of soluble and cellular interleukin-2 receptors by cord blood mononuclear cells following in vitro activation.

Cord blood mononuclear cells (CBMC) were investigated for their capacity to generate both cellular and soluble, supernatant interleukin-2 receptors (IL-2R) following cellular activation in vitro. Soluble IL-2R were measured in cell-free supernatants and in detergent-solubilized cell extracts with a "sandwich" enzyme-linked immunosorbent assay. CBMC and adult peripheral blood mononuclear cells were activated with phytohemagglutinin or the murine monoclonal antibody OKT3. CBMC and adult peripheral blood mononuclear cells generated cellular and soluble IL-2R in response to both activators. Peak values for supernatant IL-2R were observed on day 7, while peak values of cell-associated IL-2R occurred on day 5, followed by a decline on day 7. With the exception of supernatant IL-2R production induced by OKT3 stimulation, CBMC produced IL-2R in amounts comparable to adult mononuclear cells. Cord blood plasma also contained amounts of IL-2R comparable to that found in adult sera/plasma. Thus, CBMC appear largely immunocompetent with regard to the expression of IL-2R.

Adult↗

PubMed1985

A monoclonal antibody 7G7/B6, binds to an epitope on the human interleukin-2 (IL-2) receptor that is distinct from that recognized by IL-2 or anti-Tac.

Murine splenocytes immune to influenza virus-activated human T-cells were fused with SP2/0 cells, selected in chemically defined HAT media, and subcloned to yield a monoclonal antibody (MAb) termed 7G7/B6. 7G7/B6 binds to lectin- and antigen-activated T-cells, but not resting T-cells or B-lymphoblastoid lines from the same donor. 7G7/B6 immunoprecipitates a 50-55 kD band from cell surface iodinated PHA-activated T-cells or the T-cell leukemia line HUT 102B2, as shown on SDS-PAGE. Cross-clearing studies demonstrate that 7G7/B6 binds the same cell surface molecule(s) as anti-Tac, a MAb which has been shown previously to recognize the human receptor for IL-2. 35S-methionine pulse chase experiments in HUT 102B2 cells reveal that 7G7/B6 binds to an early (less than 30 min) 35-37 kD and late (greater than 4 h) 50 kD protein. Sequential immunoprecipitations demonstrate that these are identical to the molecules identified by anti-Tac under similar conditions. However, only anti-Tac coprecipitates a higher molecular band at 110 kD. 7G7/B6 and anti-Tac do not competitively inhibit the binding of each other to PHA-activated T-cells. Functional studies reveal that in contrast to anti-Tac, 7G7/B6 has almost no inhibitory effect in vitro on IL-2-driven proliferation of IL-2-dependent T-cell lines, or alloimmune cytotoxic T-cell generation (however, once generated, these cytotoxic T-cells were both 7G7/B6 and anti-Tac positive). Finally, IL-2 does not inhibit the binding of 7G7/B6 to activated T-cells under conditions which result in up to 75% inhibition of anti-Tac binding. Therefore, 7G7/B6 is another MAb recognizing the human IL-2 receptor, but binding to an epitope distinct from that recognized by either IL-2 or anti-Tac.

Antibodies, Monoclonal↗

PubMed1985

Soluble interleukin 2 receptors are released from activated human lymphoid cells in vitro.

With the use of an enzyme-linked immunoabsorbent assay to measure soluble human interleukin 2 receptors (IL 2R), certain human T cell leukemia virus I (HTLV I)-positive T cell lines were found to spontaneously release large quantities of IL 2R into culture supernatants. This was not found with HTLV I-negative and IL 2 independent T cell lines, and only one of seven B cell-derived lines examined produced small amounts of IL 2R. In addition to this constitutive production of soluble IL 2R by certain cell lines, normal human peripheral blood mononuclear cells (PBMC) could be induced to release soluble IL 2R by plant lectins, the murine monoclonal antibody OKT3, tetanus toxoid, and allogeneic cells. Such activated cells also expressed cellular IL 2R measurable in detergent solubilized cell extracts. The generation of cellular and supernatant IL 2R was: dependent on cellular activation, rapid, radioresistant (3000 rad), and inhibited by cycloheximide treatment. NaDodSO4-polyacrylamide gel electrophoresis analysis of soluble IL 2R released from either the HTLV I-positive T cell line HUT 102B2 or normal phytohemagglutinin-activated PBMC demonstrated molecules of apparent Mr = 35,000 to 40,000, and 45,000 to 50,000, respectively, somewhat smaller than the mature surface receptor on these cells. The release of soluble IL 2R appears to be a characteristic marker of T lymphocyte activation and might serve an immunoregulatory function during both normal and abnormal cell growth and differentiation.

Cell Division↗

PubMed1985

Mortality in systemic lupus erythematosus: the bimodal pattern revisited.

A review of 51 patients who died while enrolled in a long-term prospective study of systemic lupus erythematosus (SLE) revealed that active SLE may persist or reappear late in the course of the disease. Vascular events, especially atherosclerotic coronary artery disease, occurred frequently. Moderate to severe atherosclerosis was seen in patients who had died of any cause after a prolonged duration of the disease and often contributed significantly to death. Diffuse proliferative glomerulonephritis, CNS lupus and major infections were indications of poor prognosis particularly early in its course.

Adolescent↗

PubMed1984

Erosive azotemic osteoarthropathy.

Fifty-nine patients with end-stage renal disease undergoing long-term dialysis were studied prospectively for joint disease. Radiographic assessment allowed division of patients into 3 groups: group 1 included 12 patients with renal osteodystrophy and erosions of the metacarpophalangeal, proximal interphalangeal, distal interphalangeal, shoulder, wrist, and knee joints; group 2 had 11 patients with renal osteodystrophy without articular erosions; group 3 included 36 patients without osteodystrophy or erosions. Clinical manifestations were frequent in patients of group 1 and included episodes of arthralgias of the metacarpophalangeal, wrist, proximal interphalangeal, and knee joints. Patients of groups 1 and 2, particularly those of group 1, had a longer mean duration of dialysis and a higher mean serum alkaline phosphatase level compared with group 3 patients. The study indicates that there is a relatively high incidence (20%) of erosive arthropathy in dialysis patients. Renal osteodystrophy, more specifically, secondary hyperparathyroidism, and duration of dialysis are important factors in the development of this articular disorder.

Adult↗

PubMed1983

Multiple-crystal acute polyarthritis.

A patient with acute polyarthritis due to crystal-positive simultaneous gout and pseudogout affecting different joints is described. The case emphasises the importance of aspirating more than one involved joint and carefully searching for crystals in patients with acute arthritis involving 2 or more joints, particular those in whom the diagnosis of multiple crystalline joint disease is considered.

Acute Disease↗