Showing papers by "German Red Cross published in 1995"

Target structures for HIV-1 inactivation by methylene blue and light.

Abstract: In a photodynamic virus inactivation procedure for human fresh frozen plasma the plasma is exposed to visible light in the presence of 1 μM methylene blue This procedure is known to inactivate HIV-1 by at least 10632 TCID50/ml within 10 minutes To elucidate the mechanism of photo-dynamic inactivation of HIV-1 by methylene blue/light treatment, reverse transcriptase (RT), the HIV-1 associated protein p24, and viral RNA were examined In the dark, methylene blue up to 10 μM has no inhibitory effect on recombinant RT In the presence of light, recombinant RT inactivation was dependent on illumination time and the concentration of methylene blue After photoinactivation of the whole virus by methylene blue/light treatment, RT activity was also almost completely inhibited Simultaneously, it was found by Western blotting that HIV-1 p24 and gp120 are altered in size, possibly due to protein cross-linking In addition, it was shown by poly-merase chain reaction (PCR) inhibition assay that HIV-1 inactivation leads to destruction of its RNA In summary, methylene blue/light treatment acts on HIV-1 at different target sites: the envelope and core proteins, and the inner core structures RNA and RT © 1995 WiIey-Liss, Inc

Human monoclonal antibodies for the immunological characterization of a highly conserved protein domain of the hepatitis C virus glycoprotein E1.

Abstract: Although both envelope glycoproteins of the hepatitis C virus, E1 and E2/NS1, show a high degree of sequence variation, the E1 protein includes a well conserved domain, which may be functionally important. We have analysed the human B cell response to a peptide fragment from amino acid residues 314-330 (EP3) covering the central conserved sequence of this domain. Anti-hepatitis C virus-positive blood donors were screened for anti-EP3 antibodies with an ELISA based on immobilized peptide. Thirty out of 92 (32%) RIBA-confirmed donors displayed a significant antibody response to EP3. From three of these blood donors we established four anti-EP3-producing heterohybridoma cell lines: Ul/F30 and Ul/F31 produced IgM-kappa, whereas Ul/F32 and Ul/F33 secreted the isotypes IgG1-lambda and IgG1-kappa, respectively. Epitope analysis with overlapping nonapeptides suggests the existence of different antigenic determinants within the EP3 fragment. Although both IgG antibodies Ul/F32 and Ul/F33 have dissociation constants to the peptide of approximately 10(-9) M, binding to recombinant E1 protein expressed in COS-7 cells was different. Only Ul/F33 detected envelope protein of approximately 24-35 kD in Western blot. This human MoAb will be useful for further investigations on the hepatitis C virus glycoprotein E1.

Quality of pooled platelet concentrates prepared from buffy coats and stored in an additive solution after filtration

Abstract: Platelet concentrates prepared from buffy coat were pooled and stored for 6 days after removal of leukocytes by filtration. The platelets were stored in plasma or in an additive solution, Plasmalyte-A. In vitro platelet function was better preserved using Plasmalyte-A than plasma with regard to osmotic reversal and aggregation. No significant differences for the release of platelet markersΒ-thromboglobulin, platelet factor 4, or lactate dehydrogenase pre- and post-filtration and storage in plasma or Plasmalyte-A was observed. Expression of the surface membrane glycoproteins Ib, Ia/ IIa, Ilb/IIIa, and IV measured by flow cytometry after binding of monoclonal antibodies did not change during storage. The expression of activation-dependentα- granula glycoprotein GMP140, the thrombospondin, and the glycoprotein 53 from the lysosomal granules was not different between platelet pools stored in plasma or in Plasmalyte-A. The in vitro quality of platelets stored as pools is comparable for plasma and the additive solution Plasmalyte-A.