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A G Cooper

Publications and source records attributed to A G Cooper.

8 recordsLinked to original sources
PubMed1979

Loss of strain specificity of the TA3-St subline: evidence for the role of epiglycanin in mouse allogeneic tumor growth.

We described the in vivo conversion of the strain-specific ascites murine mammary adenocarcinoma subline TA3-St to a new ascites subline designated TA3-MM. This conversion occurred during passage in a syngeneic A/HeHa mouse infected with pneumonia-producing microorganisms. The mode number of chromosomes of the TA3-MM cell (82) was greater than that of the parental TA3-St cell (69) or the other non-strain-specific subline TA3-Ha (42). The TA3-MM subline could grow in and kill mice of various allogeneic strains. In addition, the TA3-MM cell possessed numerous receptors for the lectin of Vicia graminea seeds, which were hardly detectable at the surface of the parent TA3-St subline but were present in abundance at the cell surface of the non-strain-specific subline TA3-Ha. These lectin receptors of the TA3-Ha cell were previously demonstrated to be present in a unique high-molecular-weight endogenous cell surface glycoprotein termed epiglycanin. The V. gramines lectin receptors on the new TA3-MM subline also were present on an epiglycanin-like molecule. This finding provides further evidence for the hypothesis that allogeneic growth in the TA3 system is a direct result of these membrane glycoproteins.

Adenocarcinoma↗
PubMed1979

Isolation and partial characterization of an epiglycanin-like glycoprotein from a new non-strain-specific subline of TA3 murine mammary adenocarcinoma.

A new non-strain-specific ascites subline of the TA3 mammary adenocarcinoma TA3-MM, which arose in vivo from the strain-specific TA3-St subline during an acute respiratory illness of the syngeneic mouse strain A/HeHa hosts, possessed at its surface a glycoprotein not found on the parent TA3-St cell. This glycoprotein, termed TA3-MM epiglycanin, was characterized by a high molecular weight (500,000), by potent inhibition of hemagglutination by the Vicia gramines lectin, and by carbohydrate and amino acid compositions nearly identical to those of the glycoprotein epiglycanin present at the surface of the allotransplantable TA3-Ha ascites cell. By electron microscopic examination, TA3-MM epiglycanin appeared as long extended rods with widths (2.5 nm) and lengths (450--500 nm) similar to those of TA3-Ha epiglycanin. Incubation of each of two sublines of the TA3-MM ascites cell, TA3-MM/1 and TA3-MM/2, with a modified trypsin followed by column chromatography produced approximately 1.0- and 0.2-fold as much epiglycanin-like material, respectively, as was obtained from the TA3--a ascites cell. Continuous growth of the TA3-MM cell in suspension culture resulted in an almost complete disappearance of epiglycanin in a manner demonstrated earlier for the TA3-Ha cell grown under similar conditions. Allotransplantability in the TA3-MM cell may be due, at least in part, to masking a histocompatibility antigens by epiglycanin-like molecules.

Amino Acids↗
PubMed1978

Further studies on the relationship between large glycoprotein molecules and allotransplantability in the TA3 tumor of the mouse: studies on segregating TA3-HA hybrids.

In a series of six TA3-HA/A.CA hybrid cell lines formed by the fusion of the TA3-HA mammary carcinoma of a strain A mouse with a normal embryonic fibroblast of an A.CA mouse and then converted to the ascites form in parental strain A, the capacity to grow in foreign strains was inversely related to the ability to absorb anti-H-2a antibody. The absorptive capacities of the hybrid cell lines were intermediate between the low absorptive capacity of the non-strain-specific parent TA3-HA ascites cell line and the much higher absorptive capacity of the strain-specific ascites line TA3-St of the same tumor. Each hybrid cell line possessed an abundance of large endogenous cell-surface glycoprotein molecules similar to epiglycanin, a glycoprotein detected at the surface of the parent TA3-HA cell. The results suggested that the amount of epiglycanin-like material at the hybrid cell surfaces, determined by chemical and immunochemical methods, may have been directly related to the capacities of the cells to grow in foreign mouse strains and inversely related to their capacities to absorb anti-H-2a antibody.

Animals↗
PubMed1977

Regulation of cholesterol biosynthesis by normal and leukemic (L2C) guinea pig lymphocytes.

The cholesterol production of guinea pig leukemic (L2C) lymphocytes preceeds at greater than 30 times the rate found in normal cells. Fatty acid biosynthesis is also enhanced in L2C cells. Exposure of L2C cells to cholesterol/lecithin liposomes does not depress their sterol biosynthesis, in contrast to the behavior of normal lymphocytes [Philippot, J.R., Cooper, A.G. & Wallach, D. F. H. (1975) Biochim. Biophys. Acta 406, 161-166]. However, 25-hydroxycholesterol, an inhibitor of hydroxymethylglutaryl-CoA reductase (NADPH) [mevalonate: NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34], the rate limiting enzyme in cholesterogenesis, and 25-hydroxycholecalciferol, a biologically potent form of vitamin D3, block sterol biosynthesis of both normal and L2C lymphocytes [Philippot, j.r., cooper, A.G. & Wallach, D.F.H. (1976) Biochem. Biophys. Res. Commun. 72, 1035-1041]. Moreover, both cell types exchange cholesterol equivalently with cholesterol/lecithin liposomes. The only difference in sterol biosynthesis observed between the two cell types is in the temperature response of the enzyme. Arrhenius plots of this enzyme activity exhibit a prominent discontinuity at about 24 degrees in the case of normal cells, but none in the case of L2C. The activation energies for L2C cells and normal cells, above the normal cell transition temperature, were not significantly different. All of the data suggest that the regulatory defect in L2C lymphocytes arises from a deficiency in these cells' internal membranes.

Androstanes↗
PubMed1976

Demonstration of an idiotypic antigen on a monoclonal cold agglutinin and on its isolated heavy and light chains.

A potent anti-idiotype serum produced in a rabbit immunized with the isolated heavy chains of an IgM cold agglutinin "Col" was rendered specific by solid-state adsorptions. The anit-Col idiotype was shown to bind specifically to both isolated Col heavy (mu) and light (kappa) chains as well as to intact Col IgM by three methods: (i) reversal of anti-idiotype inhibition of Col cold agglutinin in an automated hemagglutination-inhibition assay system; (ii) adsorption of the anti-idiotype by affinity gels consisting of Col IgM, mu, or kappa chains covalently coupled to Sepharose 2B; (iii) binding of Col IgM and its isolated chains by an anti-idiotype affinity gel. Fragments of Col light chain lacking constant region determinants but still capable of inhibiting anti-idiotype were produced by limited pepsin digestion of the light chains. The finding of shared idiotypic determinants on isolated heavy and light chains of a monoclonal antibody suggests that these chains share a common sequence in a hypervariable region. As an extension of the gene insertion theory of Wu and Kabat, we postulate that genes coding for hypervariable regions may be available for insertion into the DNA for both heavy and light chains.

Agglutinins↗