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Biomedical subjects

E L Cooper

Publications and source records attributed to E L Cooper.

At least 91 records · Page 5Linked to original sources
PubMed1986

Second-set allograft responses in the earthworm Lumbricus terrestris. Kinetics and characteristics.

Second-set Lumbricus terrestris allografts from the same donor to the same recipient undergo accelerated rejection if transplanted less than 10 days after first-set allografts. In contrast, second-set allografts, transplanted at longer intervals (20-90 days) show no accelerated rejection. Accelerated rejection of allotransplants under these kinetic conditions agrees with earlier intrafamilial xenotransplant results obtained in earthworms affirming an essential experimental variable: the time of second-set transplantation. Accelerated rejection, weak specificity, and short-term "memory" are three characteristics of the earthworm's allogeneic cellular defense/immune system. These reactions probably result from intense responses (although of short duration) of coelomocytes activated by first transplants that are still present at the time of second-set grafting but absent or inactive at later periods.

Animals↗
PubMed1985

Purification and characterization of an O-acetylsialic acid-specific lectin from a marine crab Cancer antennarius.

A sialic acid-binding lectin with high specificity for 9-O-acetyl- and 4-O-acetylsialic acids was purified from the hemolymph of the California coastal crab, Cancer antennarius, by affinity chromatography using bovine submaxillary mucin coupled to agarose. The binding specificity of the crab lectin distinguishes it from other known sialic acid-specific lectins from Limulus polyphemus and Limax flavus which show a broader range of specificity for sialic acids. The purified lectin is homogenous on sodium dodecyl sulfate-polyacrylamide electropherograms with a subunit molecular weight of about 36 kDa. The specificity of the lectin for O-acetylsialic acids appears to account for the fact that it agglutinates mouse, rat, rabbit, and horse erythrocytes, which contain O-acetylsialic acids on cell surface glycoconjugates, but not human monkey, sheep, goat, and chicken erythrocytes which contain only NeuAc or N-glycolylneuraminic acid (NeuGc). This conclusion was supported by the potent inhibition of hemagglutination by bovine and equine submaxillary mucins which contain 9(7,8)-O-acetyl- and 4-O-acetylsialic acids, respectively, and also by free 9-O-acetyl-N-acetylneuraminic acid (9-O-Ac-NeuAc) and 4-O-Ac-NeuAc relative to NeuAc and NeuGc. Further support for the role of O-Ac-sialic acids in hemagglutination of erythrocytes was obtained by enzymatic modification of human erythrocytes. Sialidase-treated erythrocytes were resialylated with purified sialyltransferases and various CMP-sialic acid donor substrates to contain NeuAc or NeuGc or 9-O-Ac-NeuAc in the Sia alpha 2,3Gal or Sia alpha 2,6Gal linkages. Cells resialylated to contain NeuAc or NeuGc were not agglutinated, but cells resialylated to contain 9-O-Ac-NeuAc were agglutinated with high titer, comparable to that of mice or horse erythrocytes.

Animals↗
PubMed1985

Isolation, purification, and amino acid composition of the tunicate hemocyte Thy-1 homolog.

A serologic cross-reacting homolog to rodent Thy-1 glycoproteins has been isolated from hemocyte cell surfaces of the advanced invertebrate group of tunicates. The Thy-1.1 cross-reacting antigenic activity was followed during purification by inhibiting the binding of MRC OX7 monoclonal antibody to pure rat brain Thy-1 in a soluble phase radioimmunoassay. After solubilization in deoxycholate, tunicate hemocyte Thy-1.1 antigenic activity was purified by affinity chromatography using an MRC OX7 monoclonal antibody affinity column, followed by gel filtration. A 602-fold enrichment in the Thy-1.1 antigenic activity, with a yield of 55.6% compared to the starting crude membrane fraction, was obtained. The antigenic activity was associated with a single glycoprotein of molecular size of 3.1 nm and molecular weight estimated at 27,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (15% gels). Amino acid composition of the purified molecule was compared by the S delta Q index of differences in composition to mammalian and non-mammalian Thy-1 glycoproteins, Ig, major histocompatibility complex-encoded polypeptides, beta 2-microglobulin, and other recognition molecules. With this parameter, the tunicate hemocyte Thy-1 homology revealed significant relatedness to avian and mammalian Thy-1 molecules and was interestingly more related to mu chains of primitive vertebrates and to HLA class I and II encoded polypeptides than to Thy-1 molecules of higher vertebrates. Based upon these observations, the tunicate hemocyte Thy-1 homolog seems to represent an ancestral Thy-1 molecule which, in structural terms, may represent an invertebrate member of the Ig superfamily.

Amino Acids↗
PubMed1984

Serological and partial molecular characterization of a Thy-1 homolog in tunicates.

The occurrence of a Thy-1 homolog in the tissues of the advanced invertebrate group of tunicates has been investigated by using two monoclonal antibodies specific to rodent Thy-1.1 determinants and a heterologous anti-rat Thy-1 antiserum. In cellular and soluble-phase radioimmunoassays for Thy-1 using intact hemocytes, tissue extracts and hemolymph, membrane-bound and soluble Thy-1.1 cross-reacting determinants have been detected. Immunoprecipitation experiments with hemocyte deoxycholate extracts and hemolymph, labeled with 125I by lactoperoxidase/chloramine T and with NaB3H4 by galactose oxidase, established the association of the Thy-1.1 cross-reacting determinants with a single glycoprotein of apparent m.w. estimated at 27 000 in hemocytes and 22 500 in hemolymph by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The significance of this finding is discussed in relation to the phylogenetic emergence of the Thy-1 molecule during evolution.

Animals↗
PubMed1984

Earthworm leukocyte interactions during early stages of graft rejection.

The earliest phase of graft rejection in earthworms, the recognition of foreign tissue antigens, has been subjected to analysis by confronting host leukocytes with foreign erythrocytes. Only rabbit and rat erythrocytes significantly prevented healing of allografts when grafts were transplanted and erythrocytes injected simultaneously. In contrast, autografts and allografts transplanted on worms injected 1 or 2 days before grafting were never affected. Since earthworms readily produce higher titers of erythrocyte agglutinins at 24 h postinjection than at later times, we propose a hypothetical scheme of earthworm leukocyte interactions that may occur during the early phases of graft healing and of agglutinin synthesis.

Animals↗
PubMed1984

Crustacean defense strategies. I. Molecular weight dependent clearance of dyes in the mud crab Scylla serrata (Forskal) (Portunidae: Brachyura).

Clearance rates of dyes injected into the hemocoel of the mud crab, Scylla serrata, revealed several patterns of clearance and retention associated with physico-chemical and biological variables. Clearance rates remained constant: 1) when the molar concentrations of the injected dyes were equal, 2) after repeated injections of dyes and 3) after serum opsonization. Rates increased: 1) with higher molecular weight irrespective of charge, 2) at higher dye concentration and 3) at night concomitant with an increase in the hemocyte population. In contrast, clearance rates decreased with increasing crab size. Dye cleared from the hemolymph accumulated in the gills but not in the hepatopancreas, antennary glands nor gut. The retention of dyes in the gills increased with higher molecular weights. Granular hemocytes accumulated in the gill rachis and lamellae of dye treated but not in gills of normal and saline injected crabs. A role for hemocytes in molecular weight and concentration dependent clearance of dyes is suggested. Our findings are important for understanding the molecular basis of recognition in crustaceans.

Animals↗
PubMed1984

T-lymphocyte and B-lymphocyte dichotomy in anuran amphibians: II. Further investigations on the E-rosetting lymphocyte by using monoclonal antibody azathioprine inhibition and mitogen-induced polyclonal expansion.

We have continued to search for characteristics of T-lymphocytes in anuran amphibians. Inhibition assays using the monoclonal antibodies OKT-11 and T-11, the T-cell immunosuppressive drug azathioprine, and mitogens confirmed the nature of E-rosetting peripheral blood lymphocytes (PBL) in Rana pipiens. Both monoclonal antibodies specifically inhibited E-rosetting in a dose-dependent fashion; absorption of the monoclonals by frog PBL specifically removed inhibition on human E-rosetting T-cells. Lysostripping frog E-receptors with monoclonals and a second FITC antibody revealed a fluorescent lymphocyte population which capped off the receptor as shown by subsequent inhibition of E-rosetting. Significant resynthesis of E-receptors occurred 24 hours after lysostripping, especially in nylon wool effluent fractions. Azathioprine allowed us to define tentatively two subpopulations of E-rosetting lymphocytes: one nylon wool adherent and sensitive to inhibition at low concentrations and another resistant but sensitive to higher (cytotoxic) concentrations of azathioprine. In addition, T-cell but not B-cell mitogens induced expansion of E-rosetting cell populations. Our results support a thymic origin for Rana pipiens' E-rosetting cells. With respect to evolution, human and frog E-receptors are probably homologous, sharing at least one and probably two different antigenic determinants.

Animals↗
PubMed1984

T-lymphocyte and B-lymphocyte dichotomy in anuran amphibians: III. Assessment and identification of inducible killer T-lymphocytes (IKTL) and spontaneous killer T-lymphocytes (SKTL).

We have established the existence of alloreactive inducible killer (IK) T-lymphocytes in Rana pipiens by injecting immunogenic concentrations of allogeneic frog erythrocytes (RBC). Assessment of specific IK activity was determined microscopically, observing effector-target conjugate formation, and spectrophotometrically as released hemoglobin (Hb) from lysed targets (RBC). The presence of spontaneous killer (SK) T-lymphocyte activity was also determined using unimmunized frogs and similar assay conditions. Assays using rabbit anti-frog Thy-1.1 antiserum inhibition, but not E-rosetted T-lymphocyte depletion, confirmed the T-lymphocyte category of both effector cell populations in Rana pipiens. For IK activity, we determined the 1) best priming doses, 2) best effector cell source (peripheral blood), 3) best priming route (intraperitoneal), 4) kinetics of immunity development, and 5) kinetics of lysis. Kinetics of lysis and organ distribution for spontaneous killer cells were also determined. Our results may assist 1) in establishing the evolutionary origin of cytotoxic T-lymphocytes (CTL) and natural killer (NK) cells, and 2) in predicting where the capacity of immuno-surveillance against modified-self appeared in phylogeny. The implications are important for understanding origins of mechanisms of resistance against neoplastic conditions.

Animals↗
PubMed1984

Protochordate immunity--II. Diverse hemolymph lectins in the solitary tunicate Styela clava.

Hemolymph lectins (agglutinins) of the tunicate Styela clava were analyzed by agglutination, cross-absorption and carbohydrate-hemagglutination inhibition using several vertebrate erythrocytes. Lectin activity was heat labile, dependent on divalent cations and refractory to neuraminidase-treated erythrocytes. Four lectins with different carbohydrate specificities were found. Carbohydrate specificities included L-rhamnose, D-glucuronolactone, maltose, D-galactosamine, D-mannosamine, D-galactose, hyaluronic acid and bacterial lipopolysaccharide. Since S. clava lectins can be inhibited by carbohydrates found in the extracellular capsule or cell wall of most bacteria, we propose that the lectins may be part of the tunicate immuno-defense system.

Animals↗
PubMed1984

Mitogenic effect of earthworm (Lumbricus terrestris) coelomic fluid on mouse and human lymphocytes.

We have cultured mouse and human lymphocytes with earthworm (Lumbricus terrestris) coelomic fluid and measured their mitogenic responses. Normal fluid was collected from untreated worms, while induced fluid was harvested from worms injected 24 h earlier with rabbit erythrocytes. At low protein concentrations in the coelomic fluid, human and mouse lymphocytes were significantly activated, as measured by incorporation of 3HTdr. The activation index for induced fluid was approximately 2.5 times that for uninduced fluid. Separation of mouse lymphocytes into B- and T-cell populations revealed that primarily T cells were activated. Normal and induced coelomic fluid contains 12 and 28 electrophoretic bands and agglutinin titers of 32 and 1024, respectively. Addition of agglutinin inhibitors or absorption of agglutinins from coelomic fluid did not alter levels of mitogenic activity, thus the relation between earthworm agglutinins and mitogens is problematic. Techniques designed to separate and purify the agglutinins are in progress to elucidate this point.

Agglutinins↗
PubMed1984

Purification and characterization of Rana pipiens brain Thy-1 glycoprotein.

The occurrence of Thy-1 antigens in Rana brain has been studied by the use of heterologous anti-Rana brain antisera raised in rabbit and BALB/c mouse (Thy-1.2) and AKR/J mouse (Thy-1.1) strains and by monoclonal anti-mouse Thy-1.1 and anti-mouse Thy-1.2 antibodies with the use of quantitative absorption assays. Three antigenic determinants were defined on Rana brain and referred to as: 1) the Rana-specific xenoantigen, 2) the Rana-mouse cross-reacting xenoantigen, and 3) the Thy-1.1 antigen. Thy-1 antigenic activities were solubilized from crude brain membranes in deoxycholate and followed by measuring the Rana-specific and the Thy-1.1 antigenic determinants. After solubilization, Rana brain Thy-1 antigens were purified by lentil lectin affinity chromatography and gel filtration on Sephadex G-200. A 605-fold and 400-fold enrichment in the Rana-specific and the Thy-1.1 antigenic activities with a yield of 25% and 17%, respectively, were obtained. Both antigenic activities were associated with a single glycoprotein of molecular size 3.1 nm and m.w. estimated at 27,000 by SDS-polyacrylamide gel electrophoresis. The serologic and biochemical properties of our purified Rana brain Thy-1 glycoprotein were very similar to those of the mammalian Thy-1 molecule, suggesting the conservation of the gene coding for Thy-1 during vertebrate evolution.

Animals↗
PubMed1983

Serological evidences for a membrane structure related to human beta 2-microglobulin expressed by certain earthworm leukocytes.

Indirect immunofluorescence performed with 2 polyclonal and 4 monoclonal antibodies directed against human beta 2-microglobulin (beta 2m) revealed the presence of a beta 2m-like determinant on the membrane of a subpopulation of earthworm leukocytes classified as weakly adherent acidophils. Two out of the 4 monoclonal antibodies were found to bind to 15% of the earthworm leukocytes. Similar results were obtained with antibodies specific for beta 2m and isolated by affinity chromatography from either polyclonal antiserum or anti-beta 2m hybridoma supernatant. Additional binding inhibition and competition experiments strengthened the results and suggested that the homology between the structure present on earthworm leukocytes and human beta 2m may be restricted to only one major determinant. The existence of a beta 2m-like molecule in earthworms may provide important clues for understanding protein evolution and basic immune mechanisms.

Animals↗
PubMed1983

Bone marrow reconstitution of immune responses following irradiation in the leopard frog, Rana pipiens.

The bone marrow of Rana is an important source of cells capable of maintaining individual viability, responding to Concanavalin A (Con A) and producing PFC against sheep erythrocyte (SRBC) antigens. Frog marrow is more effective than the spleen in maintaining life. Radiation destroys the ability of frogs to respond to SRBC immunization (lack of bone marrow and spleen PFC, serum antibody) and bone marrow/spleen cells to respond to Con A, i.e., bone marrow and spleen contain radiation-sensitive cells. Shielding one hind leg during irradiation leads to reconstitution of bone marrow/spleen PFC responses, antibody synthesis and individual viability. Our results suggest that bone marrow is: a) the source of stem cells, and b) the source of mature T- and B- lymphocytes that can recirculate within the immune system.

Animals↗
PubMed1983

T-lymphocyte and B-lymphocyte dichotomy in anuran amphibians: I. T-lymphocyte proportions, distribution and ontogeny, as measured by E-rosetting, nylon wool adherence, postmetamorphic thymectomy, and non-specific esterase staining.

We used sheep erythrocyte (SRBC) E-rosetting, nylon wool fractionation thymectomy and nonspecific esterase staining to assess T-lymphocyte characteristics in Rana pipiens during various developmental stages. T-lymphocytes appear in the spleens of premetamorphic tadpoles. We found significant levels of lymphocytes classifiable as T-cells in the peripheral blood of adults, but fewer numbers of T-cells in the thymus, jugular bodies, spleen, pronephros, mesonephros, liver and bone marrow. In addition, thymectomized Xenopus laevis showed a sharp decrease in T-cells as evidenced by E-rosetting, ANAE stain and nylon wool fractionation. The presence of T-lymphocytes in anuran amphibians and the existence of a receptor for SRBC on a population of these cells, suggest conservation of T-cells during evolution.

Age Factors↗