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Accueil > Publications > Recherche par années > Années 1990 > 1993

1993

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Targeted plasmid-polylysine complex as putative tools to selectively transfer genes ex vivo and in vivo

Gene therapy will be an ideal method when it is possible to transfer DNA in cells with a great efficacy and an absolute safety in vivo. Along with viral carriers which are efficient but may not be strictly safe, non viral carriers could be advantageously used. Polylysine, a polycation giving stable DNA complexes, is proposed as the basis of such a carrier system. Indeed, polylysine substituted with either a protein easily taken up by cells due to specific cell surface receptors, or carbohydrate moieties which selectively interact with lectins expressed at the surface of specific cells, allows a cell specific delivery of genes. In addition, when such a targeted carrier is used together with components that protect the plasmid-targeted polylysine complex from the hydrolytic activities of lysosomes and/or help the complex to cross the cell membranes to reach the cytosol, the specificity and the efficacy of the transfection are conspicuously higher.

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Targeted plasmid-polylysine complex as putative tools to selectively transfer genes exvivo and in vivo

Gene therapy will be an ideal method when it is possible to transfer DNA in cells with a great efficacy and an absolute safety in vivo. Along with viral carriers which are efficient but may not be strictly safe, non viral carriers could be advantageously used. Polylysine, a polycation giving stable DNA complexes, is proposed as the basis of such a carrier system. Indeed, polylysine substituted with either a protein easily taken up by cells due to specific cell surface receptors, or carbohydrate moieties which selectively interact with lectins expressed at the surface of specific cells, allows a cell specific delivery of genes. In addition, when such a targeted carrier is used together with components that protect the plasmid-targeted polylysine complex from the hydrolytic activities of lysosomes and/or help the complex to cross the cell membranes to reach the cytosol, the specificity and the efficacy of the transfection are conspicuously higher.

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The immunoaugmenting properties of murine IGD reside in its C(d)1 and C(d)3 regions - potential role for IGD-associated glycans

IgD receptor (IgD-R) bearing CD4+ T cells with immunoaugmenting properties in vivo are induced in mice within 24 h after a single injection of dimeric or aggregated IgD. In the present study, we sought to identify the region(s) of IgD responsible for upregulation of IgD-R and for the immunoaugmenting effect of IgD. IgD-R can be upregulated on CD4+ T cells in vitro and in vivo by glutaraldehyde-aggregated mutant IgD or by fragments of enzymatically digested IgD molecules possessing either the C(d)1 domain (Fd(d)) or the C(d)3 domain (Fc(d)). Neoglycoproteins (D-galactose - BSA and N-acetyl-D-glucosamine - BSA), can competitively block upregulation of IgD-R by IgD in vitro. Furthermore, when injected 1 day before antigen, the aggregated IgD derived molecules, KWD1 (which lacks C(d)1), KWD6 (which lacks C(d)1 plus C(d)-hinge), and Fab(d) can all cause augmentation of antigen-specific primary and secondary antibody responses comparable to that achieved with intact aggregated IgD.

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The mechanism of action of DD-peptidases - the role of tyrosine-159 in the streptomyces R61 DD-peptidase

Tyrosine-159 of the Streptomyces R61 penicillin-sensitive DD-peptidase was replaced by serine or phenylalanine. The second mutation yielded a very poorly active protein whose rate of penicillin binding was also drastically decreased, except for the reactions with nitrocefin and methicillin. The consequences of the first mutation were more surprising, since a large proportion of the thiolesterase activity was retained, together with the penicillin-binding capacity. Conversely, the peptidase properties was severely affected. In both cases, a drastic decrease in the transferase activity was observed. The results are compared with those obtained by mutation of the corresponding residue in the class A ß-lactamase of Streptomyces albus G.

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The tetrapeptide AcSerAspLysPro (Seraspenide), a hematopoietic inhibitor, may reduce the in-vitro toxicity of 3’-azido-3’-deoxythymidine to human hematopoietic progenitors

3’-azido-3’-deoxythymidine (AZT), the main antiviral drug used in AIDS treatment, is known to induce anemia and neutropenia. These effects have been attributed to its toxicity to hematopoietic progenitors. In this report, we present a new approach to reduce AZT hematotoxicity by using an inhibitory factor of the hematopoietic stem cells, the tetrapeptide AcSerAspLvsPro (AcSDKP, Seraspenide), which has been shown to increase the survival of mice subjected to high doses of chemotherapy and to block reversibly the cycling of human granulocyte-macrophage colony forming unit (CFU-GM) and burst forming unit erythroid (BFU-E) progenitors.

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