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Biomedical subjects

M D Cooper

Publications and source records attributed to M D Cooper.

At least 343 records · Page 19Linked to original sources
PubMed1980

Immunogenicity of ribosomal preparations from Neisseria gonorrhoeae.

Protection against gonococcal infection was obtained by immunization with ribosomal preparations from Neisseria gonorrhoeae. Ribosomes were isolated from disrupted cells by differential ultracentrifugation and treatment of the microsomal fraction with 0.25% sodium dodecyl sulfate. The isolated ribosomal preparations contained 55% ribonucleic acid, 39% protein, and 0.35% carbohydrate. The ribosomal preparations contained small amounts of endotoxin as determined by thiobarbituric acid- and lead acetate-sensitized mice assays. Guinea pigs immunized subcutaneously with ribosomal preparations were challenged intrachamberially with 10(7) colony-forming units of N. gonorrhoeae, and protection was assessed by clearance of the organism from subcutaneous chambers. The ribosomal preparations elicited significant protection, which was enhanced by incoporation of the immunogen into adjuvant. This protection was comparable to that obtained with whole cells. Treatment with proteolytic enzymes destroyed the protective effect of the ribosomal preparations, but ribonuclease had no measurable effect. Passive hemagglutination and immunodiffusion tests with sera from immunized animals demonstrated the presence of antibody to the ribosomal antigens. Results of adsorption of antiribosomal sera with enzyme-treated ribosomal preparations also indicated the protein nature of the immunogen. These results indicate that protein associated with the gonococcal ribosomal preparation is the major protective immunogen. The role of endotoxin contamination in the immunogenicity of gonococcal ribosomal preparations warrants further investigation.

Animals↗
PubMed1980

Selective deposition of immunoglobulin A1 in immunoglobulin A nephropathy, anaphylactoid purpura nephritis, and systemic lupus erythematosus.

To further characterize the IgA deposits found in glomeruli of patients with IgA nephropathy, anaphylactoid purpura nephritis, and systemic lupus erythematosus, renal biopsies from patients with these disorders were stained by immunofluorescence with monoclonal anti-IgA subclass reagents, anti-light chain reagents and anti-J chain. The mesangium and peripheral capillary were brightly stained for IgA1 and were negative for IgA2. IgA1 and, to a lesser extent, IgA2 were contained in tubular casts. Both kappa and lambda light chains were found in all deposits. The intensity of J chain staining correlated with the intensity of IgM and not IgA staining. Biopsies brightly stained for IgA but negative for IgM were negative for J chain. These results indicate that glomerular IgA deposits in these disorders consist predominantly of monomers of IgA1.

Humans↗
PubMed1980

Differentiation of human B cells expressing the IgA subclasses as demonstrated by monoclonal hybridoma antibodies.

Monoclonal hybridoma antibodies to the human IgA subclasses were produced by immunizing mice with purified myeloma proteins. These antibodies were shown to be specific for the appropriate IgA subclass by enzyme-linked immunoabsorbant assay (ELISA) and by immunofluorescent staining of myeloma plasma cells and B cells from normal individuals. These antibodies were used to demonstrate age-related shifts in the proportions of IgA1- and IgA2-bearing B cells that could be correlated with 3 distinct staining patterns. In the newborn equal numbers of IgA1 and IgA2, B cells were found. These cells had only small amounts of surface IgA in a patchy distribution. They also expressed surface IgM. In the infant, large lymphoblastoid cells were observed that bore more IgA in a homogeneous pattern but did not express IgM. Of these cells, 98% were positive for IgA1. In the adult, 80% of the IgA B cells were positive for surface IgA1, and 20% were positive for IgA2. These were small lymphocytes brightly stained for IgA and negative for IgM. In culture, the adult B cells responding to pokeweed gave rise to roughly equal numbers of IgA1 and IgA2 plasma cells. These results suggest that there are equal numbers of precursor cells for IgA1 and IgA2 whose expansion, further differentiation, and migration are selectively affected by immunoregulatory controls.

Animals↗
PubMed1979

Studies on the clonal origin of multiple myeloma. Use of individually specific (idiotype) antibodies to trace the oncogenic event to its earliest point of expression in B-cell differentiation.

IgA myeloma proteins of kappa- and lambda-types were isolated from two patients. These were used to produce and purify anti-idiotype antibodies of both broad (myeloma-related) and narrow (individual myeloma) specificities. The anti-idiotype antibodies were conjugated with fluorochromes and used as immunofluorescent probes to trace in the patients clonal expansion at different levels of B-cell differentiation. Our results (a) confirm that B lymphocyte precursors in IgA plasma-cell myelomas are involved in the malignant process, (b) show that B lymphocytes of the malignant clone include those expressing each of the major heavy-chain isotypes, mu, delta, gamma, and alpha, and (c) provide strong circumstantial evidence that pre-B-cell members of the malignant clone are also increased in frequency. T cells expressing idiotypic determinants were not detected. These findings argue that the initial oncogenic event may occur in a B-stem cell and is not influenced through stimulation by antigen. An interesting association was the increased frequency of related clones of B lymphocytes as detected by their reactivity with anti-idiotype antibodies of broad specificity. Neither plasma cell nor pre-B-cell members of these related clones were increased in frequency. Anti-idiotype antibodies or helper T cells reactive with myeloma-related idiotypes could be responsible for this phenomenon. We discuss other implications of these findings and speculate that all of the various phenotypes of B-lineage malignancies may result from oncogenic processes affecting stem cell targets.

Antibodies, Neoplasm↗
PubMed1979

Immunologic properties of soluble materials from Brucella species.

The purpose in this study was to examine the immunogenic properties of various preparations of aqueous ether extracts of Brucella suis and Brucella canis. The B suis strain 3b and B canis strain RM-6-66 were grown on tryptose agar, and aqueous ether extracts were prepared from the cells. The ether was removed, and the extracts were clarified by centrifugation for 10 hours at 144,000 X g and fractionated by gel chromatography. The B suis endotoxin-containing precipitate, obtained from aqueous ether extracted material by ethanol precipitation, and fraction 1, prepared from ultracentrifugal supernate by column chromatography, protected mice against homologous infection. The B canis aqueous ether-extracted material also protected mice against B suis infections.

Animals↗
PubMed1978

Pre-B and B cells in rabbits. Ontogeny and allelic exclusion of kappa light chain genes.

Pre-B cells in developing rabbits were identified by immunofluorescence as cells containing small amounts of cytoplasmic IgM (cIgM) but lacking surface immunoglobulin (sIg). During ontogeny the first pre-B cells appeared in fetal liver at 23 days gestation, 2 days before the appearance of sIgM+ B lymphocytes. Pre-B cells were relatively frequent in fetal and adult bone marrow, but were not found in other tissues except rarely in fetal spleen. Allelic exclusion is apparently established at this early stage of development, because individual pre-B cells and B lymphocytes from heterozygous rabbits expressed only one of the alternative alleles in amounts sufficient for detection. Development of isotype diversity among rabbit B lymphocytes followed the general pattern seen in mouse and man. sIgM+ cells were detected before birth. Expression of sIgG was detected in neonatal rabbits on cells which were also sIgM+ but in older animals most sIgG+ cells lacked sIgM. Cells bearing sIgA were not found until 5-6 days of age, and had no other isotype on their surface.

Alleles↗
PubMed1978

Turnover of hepatic phosphofructokinase in normal and diabetic rats. Role of insulin and peptide stabilizing factor.

Earlier work demonstrated that the activity of liver phosphofructokinase (PFK-L2) and immunoreactive PFK-L2 were decreased in diabetic rats and increased to normal or super-normal amounts following insulin treatment (Dunaway, G.A., and Weber, G., (1974) Arch. Biochem. Biophys. 162, 629-637). This report indicates that the decrease in levels of PFK-L2 in diabetic rats is a result of an accelerated degradation rate while the synthetic rate remains nearly normal. Following insulin treatment, the rate of PFK-L2 synthesis is enhanced 2-fold, whereas the rate of degradation appears to be greatly diminished. An inverse relationship is shown to exist between the PFK-L2 levels and the rates of PFK-L2 degradation, suggesting that the levels of PFK-L2 are primarily regulated by degradation rate. In addition, the levels of the PFK-L2 peptide stabilizing factor are inversely proportional to rates of PFK-L2 degradation. These results indicate that insulin mediates the rate of degradation of PFK-L2 by controlling the level of the peptide stabilizing factor.

Animals↗
PubMed1978

Morphological and histochemical analyses of two human T-cell subpopulations bearing receptors for IgM or IgG.

Two subpopulation of circulating human T cells forming rosettes with neuraminidase-treated sheep erythrocytes were purified on the basis of the presence of receptors for IgG (TG cells) or for IgM (TM cells), and were shown to have distinguishing morphological and histochemical characteristics. TM cells had the general features of typical small- or medium-sized lymphocytes; most were easily identifiable by distinctive cytoplasmic accumulations, usually one and sometimes two large spots, of nonspecific acid esterase activity. The release of the vesicular contents on short-term culture of TG cells was inhibited by cytochalasin B. Definition of these distinguishing characteristics of TM and TG cells provides a basis for practical enumeration of these functionally distinct subpopulations of human T cells. Some of the TG cells were capable of endocytosis of IgG antibody-coated erythrocytes.

Binding Sites, Antibody↗
PubMed1978

Pre-B-cell leukemia. A new phenotype of childhood lymphoblastic leukemia.

Large lymphoid cells containing small amounts of cytoplasmic IgM (clgM) but undetectable surface immunoglobulin (slg) have recently been recognized as precursors of B lymphocytes. They are a small, rapidly dividing pool of normal marrow lymphoblasts. Since lymphoblasts in most childhood acute lymphoblastic leukemias lack slg and other conventional B-lymphocyte and T-lymphocyte markers, we examined the possibility that some leukemias represent "pre-B"-cell neoplasms. In four of 22 consecutive patients, leukemic cells had the clgM+.slg- phenotype of pre-B cells. These patients' cells shared "common acute-lymphoblastic-leukemia" antigens and "B-cell" alloantigens, but differed in expression of several developmental features characteristic of the B-cell line. Pre-B-cell leukemias were readily responsive to chemotherapy. We conclude that a distinct subpopulation of previously unclassified leukemias reflects oncogenic transformation at the earliest recognizable stage in differentiation along the B-cell axis.

Adolescent↗