Type I allergy, an immunodisorder affecting almost 20% of the population worldwide, is based on the production of IgE antibodies against per se harmless allergens. We report the expression of hexahistidine-tagged antibody fragments (Fabs) with specificity for Bet v1, the major birch pollen allergen, in Escherichia coli. The cDNA coding for the heavy chain fragment of a mouse monoclonal anti-Bet v1 antibody, Bip 1, was engineered by PCR to contain a hexahistidine-encoding 3' end. The modified Bip1 heavy chain cDNA was co-expressed in E. coli XL-1 Blue with the Bip 1 light chain cDNA using the combinatorial plasmid pComb3H. His-tagged recombinant (r) Bip 1 Fabs were isolated by nickel affinity chromatography and rBip 1 Fabs without His-tag were purified via affinity to rBet v1. rBip 1 Fabs with and without His-tag bound specifically to rBet v1 and, like Bet v1 -specific human serum IgE and rabbit-anti rBet v1 antibodies, cross-reacted with Bet v1-related allergens in other plant-species (alder, oak, hazelnut). We demonstrate the usefulness of His-tagged rBip 1 Fabs (1) for the identification of pollen samples containing Bet v 1 by particle blotting, (2) forthe detection of Bet v1-specific IgE antibodies in human serum samples by sandwich ELISA and (3) for the quantification of Bet v1 in solution. Based on these examples we suggest to use rBip 1 Fabs for the detection of Bet v1 and Bet v1-related allergens in natural allergen sources for allergy prevention, as well as for the standardization of natural allergen extracts produced for diagnosis and immunotherapy of birch pollen allergy.

Intradural disc herniation is a rare entity reported at 0.04–1.1% that occurs most commonly in the lumbar spine particularly at L4–L5 region. There is a paucity of literature due to the rarity of this condition. Intradural disc herniations must be considered in the differential diagnosis of prolapsed intervertebral disc disease especially with recent worsening of symptoms and mismatch of unenhanced magnetic resonance induction (MRI) findings. The confirmation is made with intraoperative findings. An intradural disc herniation is most often diagnosed intraoperatively. Contrast enhanced MRI scan is mandatory for pre-operative diagnosis. We report on two cases presenting to our unit in the form of recurrent intradural disc disease following previous lumbar surgery occurring within 3 months of the index procedure in both cases.

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