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B Hübner

Publications and source records attributed to B Hübner.

12 recordsLinked to original sources
PubMed2001

Functional and structural similarity of V gamma 9V delta 2 T cells in humans and Aotus monkeys, a primate infection model for Plasmodium falciparum malaria.

Gammadelta T cells are implicated to play crucial roles during early immune responses to pathogens. A subset of human gammadelta T cells carrying the Vgamma9Vdelta2 TCR recognize small, phosphorylated nonpeptidic Ags. However, the precise role of these cells and the ligands recognized in human immune responses against pathogens remains unclear because of the lack of suitable animal models. We have analyzed the reactivity of spleen cells of the New World monkey Aotus nancymaae against isopentenyl pyrophosphate (IPP), a phosphorylated microbial metabolite selectively activating Vgamma9Vdelta2 T cells. Spleen cells were stimulated by IPP and the expanding cell population expressed the Vgamma9 TCR. TRGV-J and TRDV-D-J rearrangements expressed by IPP-stimulated cells of Aotus were analyzed by RT-PCR and DNA sequencing. The TRGV-J and TRDV-D-J rearrangements expressed by IPP-stimulated Aotus and human gammadelta T cells were similar with respect to 1) TCR gene segment usage, 2) a high degree of germline sequence homology of the TCR gene segments used, and 3) the diversity of the CDR3 regions. Phylogenetic analysis of human, Pan troglodytes, and A. nancymaae TRGV gene segments showed that the interspecies differences are smaller than the intraspecies differences with TRGV9 gene segments located on a distinct clade of the phylogenetic tree. The structural and functional conservation of Vgamma9Vdelta2 T cells in A. nancymaae and humans implicates a functionally important and evolutionary conserved mechanism of recognition of phosphorylated microbial metabolites.

Amino Acid Sequence↗
PubMed2001

Herpesvirus saimiri transformed T cells and peripheral blood mononuclear cells restimulate identical antigen-specific human T cell clones.

Panels of human antigen-specific T cell clones (TCC) have been established by limiting dilution using Herpesvirus saimiri (HVS) subtype C transformed T cells as antigen presenting cells (APC). They showed antigen-specific proliferation when peripheral blood mononuclear cells (PBMC), HVS-transformed T cells and Epstein Barr Virus transformed lymphoblastoid B cell lines (EBV-LCL) were used as APC. All T cell clones were CD4+ and HLA class II restricted. For a detailed analysis, two panels of T cell clones specific for an epitope located in the N-terminus of the Merozoite Surface Protein 1 (MSP-1) of Plasmodium falciparum were established from the same founder T cell line using either PBMC or HVS-transformed T cells as APC. TCR analysis of the two panels of TCC demonstrated that the same founder cells could be propagated in both culture systems. Furthermore, no difference in the cytokine expression pattern or antigen processing and co-stimulatory requirements was observed between TCC established on PBMC or HVS-transformed T cells. Based on the finding that HVS-transformed T cells can replace PBMC as APC for isolation and propagation of antigen-specific TCC, a protocol was developed and successfully executed, which allows to establish and maintain vaccine-specific T cell clones from 20 ml of blood. This method might be particularly significant in clinical trials of immune intervention strategies.

Amino Acid Sequence↗
PubMed2000

Rapid identification of Enterobacteriaceae using a novel 23S rRNA-targeted oligonucleotide probe.

The aim of this study was to rapidly identify bacteria of the family of Enterobacteriaceae using fluorescent in situ hybridization (FISH). A comparative sequence analysis was carried out and a 23S rRNA signature sequence for Enterobacteriaceae was identified. A 23S rRNA-targeted oligonucleotide probe (EBAC1790) was constructed and subsequently tested against 40 reference strains. Nearly all of the Enterobacteriaceae used in this study yielded positive results with EBAC1790, except for Edwardsiella tarda (ATCC 15947). None of the non-Enterobacteriaceae reference strains gave positive signals with the probe. The possibility of a rapid detection of Enterobacteriaceae in groundwater was demonstrated using colony hybridization.

Enterobacteriaceae↗
PubMed1997

Differential effect of purified spruce chitinases and beta-1,3-glucanases on the activity of elicitors from ectomycorrhizal fungi.

Two chitinases (EC 3.2.1.14) and two beta-1,3-glucanases (EC 3.2.1.39) were purified from the culture medium of spruce (Picea abines [L.] Karst.) cells to study their role in modifying elicitors, cell walls, growth, and hyphal morphology of ectomycorrhizal fungi. The 36-kD class I chitinase (isoelectric point [pl] 8.0) and the 28-kD chitinase (pl 8.7) decreased the activity of elicitor preparations from Hebeloma crustuliniforme (Bull. ex Fries.) Quél., Amanita muscaria (L.) Pers., and Suillus variegatus (Sw.: Fr.) O.K., as demonstrated by using the elicitor-induced extracellular alkalinization in spruce cells as a test system. In addition, chitinases released monomeric products from the walls of these ectomycorrhizal fungi. The beta-1,3-glucanases (35 kD, pl 3.7 and 3.9), in contrast, had little influence on the activity of the fungal elicitors and released only from walls of A. muscaria some polymeric products. Furthermore, chitinases alone and in combination with beta-1,3-glucanases had no effect on the growth and morphology of the hyphae. Thus, it is suggested that apoplastic chitinases in the root cortex destroy elicitors from the ectomycorrhizal fungi without damaging the fungus. By this mechanism the host plant could attenuate the elicitor signal and adjust its own defense reactions to a level allowing symbiotic interaction.

Amanita↗
PubMed1995

Synergistic interactions between interferon beta and carboplatin on SK-MEL 28 human melanoma cell growth inhibition in vitro.

Carboplatin and interferon beta (IFN beta) were tested alone and in combination for their antiproliferative activity on the human melanoma cell line SK-MEL 28 in vitro. Cells were incubated for 4 days in the presence of carboplatin (0.1 mM and 0.1 microM) and interferon beta (5 pM and 5 nM) and cell growth inhibition was determined by the sulphorhodamin B assay. The antiproliferative effects of the drug combinations were analysed using Berenbaum's hyperplane theorem to determine additive, synergistic and antagonistic effects. IFN beta was found to be 10,000 times more active in inhibiting cell growth of SK-MEL 28 cells than carboplatin on the basis of IC50 values (IFN beta: IC50 = 1.24 nM, carboplatin: IC50 = 18.2 microM). The addition of IFN beta at 0.5 nM reduced the IC50 value of carboplatin 18.0-fold; with IFN beta at 0.05 nM a dose reduction of 1.84 was measured. At the carboplatin: IFN beta molar concentration ratios of 2000:1 and 6000:1, interaction indices (I) of 0.66 and 0.83 were determined respectively, indicating synergistic interactions between the two drugs. At higher carboplatin: IFN beta molar ratios (20,000:1 and 60,000:1) an additive interaction was observed (I = 1.07 and 1.20). However, further in vitro studies with several melanoma cell lines are necessary to evaluate the potential effectiveness of the drug combination of carboplatin and IFN beta for eventual clinical utilisation.

Carboplatin↗
PubMed1981

[A double-blind comparison of epidural buprenorphine and epidural morphine in postoperative pain (author's transl)].

Morphine (5 mg) and buprenorphine (0.15 mg) given by the epidural route were compared in 50 patients recovering from abdominal surgery. Pain relief score, sedation score and clinical measures were evaluated in a double-blind study. Both substances produced thorough analgesia with short latency (2-6 min) of long duration (8-9 h). Side effects were encountered in some morphine cases only, but never therapy had to be discontinued. Total lack of side effects with buprenorphine favours its application in epidural pain relief.

Anesthesia, Epidural↗