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B Bohle

Publications and source records attributed to B Bohle.

40 records · Page 3Linked to original sources
PubMed1995

Hydrocortisone enhances total IgE levels--but not the synthesis of allergen-specific IgE--in a monocyte-dependent manner.

Recently, hydrocortisone (HC), when combined with human IL-4, has been reported to increase IgE levels in supernatants (SN) of in vitro cultured leucocytes. In this study we investigated the influence of HC on allergen-specific IgE synthesis. Moreover, we examined the relevance of different cell types in this respect. Peripheral blood mononuclear cells (PBMC), T-cell depleted PBMC, CD14-depleted PBMC and highly purified B cells from 10 allergic (birch pollen and/or grass pollen) patients and five non-allergic individuals were investigated. The cells were incubated with HC and/or recombinant human IL-4 (rIL-4) for 8 days. A considerable increase of total IgE was observed in HC/rIL-4-stimulated cultures compared with rIL-4 alone, HC alone or non-stimulated cultures. We demonstrate that this effect depends on the presence of monocytes in in vitro cultures. These results were seen in every experiment, irrespective of healthy or atopic state of the blood donor. The increase of IgE could not be attributed to a rise of birch pollen-and/or grass pollen-specific IgE in patients allergic to these allergens, as shown by IgE-immunoblot. Radio-allergosorbent test (RAST) investigations of HC/rIL-4-stimulated cells cultures from allergic and non-allergic patients confirmed that HC/rIL-4-induced elevated IgE production was also not due to increased production of IgE, specific for important aero-allergens (pollens, house dust mite or animal dander). Therefore we conclude that newly synthesized IgE is not specific for allergens, but that sequential isotype switching in human B cells leads to increased polyclonal IgE production.

Allergens↗
PubMed1993

Purification and characterization of recombinant Bet v I, the major birch pollen allergen. Immunological equivalence to natural Bet v I.

Pollen from trees of the order Fagales (e.g. birch, alder, hazel, oak, and hornbeam) are a major cause of Type I allergies observed in early spring. Previously, we reported the cloning and sequencing of Bet v I, the major birch pollen allergen, which showed high sequence similarities to a family of plant pathogen-activated genes (Breiteneder, H., Pettenburger, K., Bito, A., Valenta, R., Kraft, D., Rumpold, H., Scheiner, O., and Breitenbach, M. (1989) EMBO J. 8, 1935-1938). Here, we present the results on the expression, purification, and characterization of recombinant Bet v I produced in Escherichia coli as fusion and non-fusion protein, respectively. The purified recombinant proteins were analyzed to verify purity and structural integrity, and their immunological properties were compared to those of Bet v I isolated from birch pollen (natural Bet v I). Immunoblot analyses showed that the recombinant proteins are specifically recognized by monoclonal antibodies raised against natural Bet v I as well as by IgE from birch pollen-allergic patients. However, enzyme-linked immunosorbent assays revealed a decreased IgE-binding activity of the recombinant fusion Bet v I compared to the non-fusion and natural Bet v I proteins, which probably results from conformational changes due to the fusion tail. Recombinant non-fusion Bet v I was equivalent to natural Bet v I with respect to IgE-binding properties, the ability to induce in vitro proliferation of allergen-specific T-cell clones, and the ability to release histamine from basophils derived from birch pollen-allergic patients.

Allergens↗
PubMed1991

The immunological relationship of epitopes on major tree pollen allergens.

The major allergens of birch (Bet v I), alder (Aln g I), hazel (Cor a I) and hornbeam (Car b I) were investigated by means of high-resolution two-dimensional electrophoresis combined with immunoblotting. Eleven sera derived from patients allergic to birch pollen as well as mouse monoclonal antibodies BIP 1 and BIP 4, raised against Bet v I, were used as probes. Human IgE antibodies detected 10 spots in birch (Mr 17 kDa, pI 4.9-5.9); four spots in alder (Mr 18.5 kDa, pI 4.7-5.3); four spots in hazel (Mr 17 kDa, pI 5.0-5.8); and 12 + 7 spots in hornbeam (Mr 16.5 kDa, pI 4.9-6.6 and Mr 18 kDa, pI 5.2-6.7), respectively, representing major allergens. Each patient tested reacted in a similar fashion with the spot cluster(s) of a certain allergen. BIP 1 detected the same spot clusters as patients' IgE. BIP 4 reacted with the 17-, 18.5- and 18-kDa spots of birch, alder and hornbeam, but did not react with the 17-kDa spots of hazel and the 16.5-kDa spots of hornbeam. In inhibition experiments with birch pollen extract as inhibitor, IgE binding to Bet v I, as well as to Aln g I, Cor a I and Car b I was abolished, thus suggesting that IgE binding to major tree pollen allergens is confined to shared epitopes. These findings indicate that it might be sufficient to use only Bet v I for diagnostic procedures as well as for immunotherapy in patients with tree pollen allergy.

Adolescent↗