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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Vaccine 6 (1988), S. 75-76 
    ISSN: 0264-410X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1076
    Keywords: Mother-to-child transmission ; HIV-1 ; IgA antibodies ; Peptide-ELISA ; Time-resolved fluoro-immunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The presence of specific IgA antibodies in sera from 25 infants born to HIV-1 seropositive mothers was investigated by peptide-ELISA and peptide time-resolved fluoro-immunoassay (TR-FIA). The infants had been monitored at different times after birth for clinical signs and/or symptoms of HIV-1 infection and for detection of HIV-1 in lymphocyte cultures. Serum samples had also been tested for HIV-1 IgG antibodies by commercial ELISA and Western blot and for p24 antigen. Eleven of 25 children were then identified as infected. IgA detection was performed after rProtein G treatment to remove interfering IgG. In the infected group, IgA specific antibodies to a synthetic peptide representing a highly conserved region of the transmembrane glycoprotein gp41 (env: 594–613) were detected in 27 (73%) out of 37 serum samples (9 of 11 children) by the peptide-ELISA test. IgA specific antibodies to the same peptide were found in 30 (81%) sera (9 of 11 children) by the peptide-TR-FIA. Specific HIV-1 IgA antibodies were detected as early as 2 months of age in serum samples from five out of seven children (71% sensitivity) using peptide-ELISA and from six out of seven (86% sensitivity) by peptide-TR-FIA. Conversely, IgA specific antibodies to HIV-1 were absent in two infected children as well as in the sera of all uninfected children tested during the follow up period. Since maternal IgA does not cross the placenta, IgA detection in the serum of the infant is indicative of HIV-1 infection. Indeed, the early demonstration of HIV-1 IgA antibodies in infected infants shows that both peptide-ELISA and peptide-TR-FIA can be used for an early diagnosis of HIV-1 infection.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A DNA fragment encoding the CD4-binding region of human immunodeficiency virus type 1 (HIV) gp120 was excised from an SV40-based expression vector containing gp160, and subcloned into phage M13 for site-directed mutagenesis. Mutant vectors were constructed and CV-1 cells were transfected with constructs, where Cys402 was substituted for a serine, and metabolically labelled with [3H]-N-acetylglucosamine (GlcN). Radioimmunoprecipitation with an hyperimmunserum, specific for gp120/gp160, and subsequent SDS-polyacrylamide gel electrophoresis demonstrated presence of gp160, whereas gp120 was replaced by [3H]-GlcN-labelled material, migrating as a diffuse band corresponding to 80–105k, suggesting increased sensitivity of mutantenv gene products to proteolysis after cleavage to gp120. Wild type gp120 and gp160 bound to CD4, whereas neither gp160 nor gp120 from mutant-transfected cell lysates did bind to CD4. Altogether the results indicated that Cys402, probably by participating in a disulfide bridge, is essential for (i) the CD4-binding ability ofenv gene products and for (ii) the physical stability of gp120.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have used a bovine papilloma virus (BPV) based mammalian cell expression vector consisting of the complete BPV genome and a human cytomegalovirus transcription unit for the production of soluble CD4. Mouse C-127 cells were transfected with vector DNA together with a selectable G418 resistance plasmid. Surviving clones were selected for high production using a solid phase ELISA based on the immobilization of supernatant-derived CD4 onto nitrocellulose paper and subsequent detection with anti-CD4 antibodies. The expressed protein was shown to bind HIV-gp120 and efficiently block HIV-1 infection in vitro. The possibility to use the above system for rapid production of defined glycoprotein fragments harboring defined functional regions, for the further elucidation of the functional role of CD4 in antigen presentation and cell to cell contact, and for possible intervention during HIV infection is discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0851
    Keywords: Monoclonal antibodies ; Network response ; Anti-idiotype antibodies ; T cells ; Colon carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The antitumor effector functions of unconjugated monoclonal antibodies in cancer therapy are complex. Direct cytotoxic mechanisms such as antibody-dependent cellular cytotoxicity, complement-dependent cytolysis and apoptosis have been suggested. Induction of anti-idiotypic (ab2) and anti-anti-idiotypic (ab3) antibodies as well as T cell (T2 and T3 respectively) responses have also been proposed to be of clinical importance. In this study induction of an immune network cascade in patients with colorectal carcinoma, treated with mAb 17-1A (ab1) was assessed. All patients developed anti-idiotypic antibodies (ab2) of the IgG class after treatment with ab1 and four of nine patients showed induction of mouse Ig reactive T cells [a proliferative response to F(ab′)2 fragments of ab1]. Patients with such a T cell response developed anti-anti-idiotypic antibodies (ab3), while those lacking the T cell reactivity failed to mount an ab3 response. Three of four patients with a T cell response achieved a tumor response to mAb therapy. Thus, all responding patients belonged to the group of individuals developing ab3. Induction of mAb(ab1)-reactive T cells as well as an immune network cascade might be important antitumor effector functions of mAb and should be considered in the future design of mAb-based therapy protocols in cancer patients.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0851
    Keywords: Key words: Monoclonal antibodies – Network response – Anti-idiotype antibodies – T cells – Colon carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The antitumor effector functions of unconjugated monoclonal antibodies (mAb) in cancer therapy are not fully understood. Direct cytotoxic mechanisms such as antibody-dependent cellular cytotoxicity, complement-dependent cytolysis and apoptosis have been suggested. Induction of anti-idiotypic (ab2) and anti-anti-idiotypic (ab3) antibodies as well as the corresponding T cells (T2 and T3) has also been proposed to be of therapeutic significance. In this study induction of an immune network cascade in ten patients with colorectal carcinoma, treated with mAb 17-1A (ab1) was assessed. After treatment, all ten patients had anti-idiotypic antibodies and anti-anti-idiotypic antibodies with ab1-like binding specificity while only five of ten patients had T cells corresponding to ab3 (T3) as assessed by a proliferation assay (DNA synthesis), and an assay of interferon γ production (ELISPOT) (Enzyme-linked immuno SPOT) in vitro or by a delayed-type hypersensitivity reaction in vivo. Purified T cells from four of the five patients with a positive T3 test responded with DNA synthesis after stimulation using human anti-mAb 17-1A anti-idiotypic monoclonal antibodies. These four patients had a clinical response showing a tumor reduction after therapy, while all six patients lacking a proliferative response failed to show tumor regression. Induction of a cell-mediated immune network cascade might accordingly be an important antitumor effector function of mAb and should be considered in the future design of mAb-based therapy protocols in cancer patients.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sarcoma P1 was induced in DA rats by DMBA. Anti-P1 antibodies were produced in DA rats, purified via fixed tumor cells and used to induce anti-idiotypic antibodies in syngeneic rats. The anti-idiotypic antibodies were used to generate cytotoxic, P1 specific DA T cells in vitro. These cytotoxic T cells and P1 tumor cells were cloned by limiting dilution. Using the DA anti-P1 specific cytotoxic T cell clones, we were able to characterize 2 types of P1 tumor cell clones, namely those which were susceptible and those which were resistant to the P1 specific cytotoxic T cells. Cytotoxic T cell injected i.v. into syngeneic DA rats could not prevent the development of lethal P1 tumors.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1591-9528
    Keywords: Lymphocytes, subpopulations ; Lymphocytes, functional heterogeneity ; Lymphocytes, immunoglobulin determinants ; Lymphocytes, receptor sits for immune complexes ; Lymphocyten, Subpopulationen ; Lymphocyten, funktionelle Heterogenität ; Lymphocyten, Immunglobulindeterminanten ; Lymphocyten, Oberflächenreceptoren für Immunkomplexe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Aus verschiedenen Organen isolierte lymphatische Zellen wurden auf das Vorhandensein von Immunglobulindeterminanten an ihrer Oberfläche und auf Receptoren für Antigen-Antikörper-Komplementkomplexe untersucht. Durch simultane Untersuchungen konnte gezeigt werden, daß beide untersuchten Zellpopulationen in der Milz und im Lymphknoten in Ähnlicher Häufigkeit nachgewiesen werden können, während sie in Thymuszellsuspensionen weitgehend fehlten. Wurden Lymphocyten mit Immunglobulindeterminanten durch Zusatz von Anti-leichte Ketten-(Kappa-)Antiseren und Komplement lysiert, so erniedrigte sich der Prozentsatz von CRL unter den überlebenden Zellen deutlich. Im Gegensatz dazu war der Anteil von CRL nach Vorbehandlung von Lymphocyten mit Anti-Thymuszellen-Antiserum oder mit Anti-θ-Antiserum und Komplement stark erhöht. Wurden Lymphocytensuspensionen durch Zentrifugation in einem diskontinuierlichen Albumingradienten von CRL gereinigt, so konnte ein gleichzeitiger Verlust von Zellen mit Immunglobulindeterminanten beobachtet werden. Im Gegensatz dazu stieg in den so behandelten Zellsuspensionen der Anteil von Lymphocyten, die mit Anti-Thymuszellen-Antiserum oder mit Anti-θ-Antiserum reagierten, deutlich an. Schließlich konnten Immunglobulindeterminanten durch eine kombinierte Methode an etwa 85% der CRL dargestellt werden, während dies nur an einem vergleichsweise geringen Teil der non-CRL (etwa 15%) beobachtet werden konnte. Aus diesen Befunden schlossen wir, daß beide untersuchten Eigenschaften Marker ein und derselben „knochenmarksabhängigen“ Lymphocytenpopulation darstellen und diskutierten die Bedeutung dieser Zellen bei der Anreicherung von Antigenen in bestimmten Abschnitten des lymphatischen Systems.
    Notes: Summary On mice lymphocytes isolated from thymus, lymphnodes and spleen we investigated the portion of cells bearing immunoglobulin determinants and those with receptor sites for antigen-antibody-complement complexes (CRL). Lymphocytes with immunoglobulin determinants were evaluated by fluorescent staining and by cytotoxic assays employing anti kappa antisera. CRL were detected by incubating lymphocytes with sensitized and complement coated red cells (EAC). Both cell populations were found in similar frequency in cell suspensions of lymphnodes and spleens, whereas in the thymus both were almost missing. If lymphocytes bearing immunoglobulin determinants were lysed by addition of anti kappa antiserum and complement, the percentage of CRL within the surviving cells was very markedly reduced. By contrast a comparable increase of CRL was observed after pretreatment of spleen cells with anti thymocyte antiserum or with antiθ antiserum and complement. By centrifugation in a discontinous albumin gradient lymphocyte suspensions containing a very low number of CRL were obtained. These suspensions were enriched of lymphocytes reacting with anti thymocyte antiserum and with antiθ antiserum, but deficient on cells with immunoglobulin determinants. After staining lymphocytes bearing immunoglobulin determinants with appropriate fluorescent antisera they were incubated with EAC. By these means both markers were simultaneously evaluated. Immunoglobulin determinants were demonstrated on about 85% of CRL, but only on 15% of non-CRL. From these experiments we concluded a close correlation between lymphocytes bearing immunoglobulin determinants and CRL. Both features were primarily present on so called bone marrow derived cells.
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  • 9
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: T cells are essential in the initiation and maintenance of immune responses. Specific interaction between T cells and a presumptive antigen occurs through recognition of an MHC—peptide complex by the T-cell receptor (TCR). The complementarity-determining region (CDR) 3 of the TCR has direct contact with the peptide. Here we describe CDR3 length variability of six different TCRBV gene families of CD4+ and CD8+ umbilical cord (UC) and peripheral blood (PB) T cells. Amplified products spanning the TCR CDR3 regions from CD4+ PB, CD4+ UC and CD8+ UC blood T cells typically displayed Gaussian-like distributions. In contrast, profound and frequent perturbations were recorded in CD8+ PB lymphocytes, with a non-Gaussian pattern in more than half of the samples studied. A substantial portion of the perturbed CD8+ subsets were clonal or oligoclonal, as determined by CDR3-length restriction, TCRBJ gene usage and nucleotide sequencing. This implies that the conditions for shaping and maintenance of the peripheral TCR repertoire are profoundly different for CD8+ and CD4+ T cells.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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