RAPE POLLEN ALLERGY
In 1948 Juhlin-Dannfelt published his investigation of the occurrence of different types of pollen allergy in Sweden. According to Urbach (1937) and Hansen (1940), certain regions of Europe have only one pollen season. Juhlin-Dannfelt showed that there are two pollen seasons in Sweden, one in spring in which catkin bearing trees play an important role, and the other in June and July, months in which the grass pollens predominate. Juhlin-Dannfelt also reported hypersensitivity to other types of pollen, especially from some Compositae, particularly the oxeye daisy. He also described isolated instances of allergy to pollen from the genera of Taraxacum, Rumex, Plantago and Chenopodium. Recently a man presented himself at the department of allergy complaining of asthma and pollinosis, which on investigation proved to be due to hypersensitivity to rape pollen. As a search of the literature failed to reveal any reports of hypersensitivity to pollen from plants belonging to the Cruciferae family, a brief description of the case observed was considered justified.
Identification of Oilseed Rape (Brassica napus) Pollen Profilin as a Cross-Reactive Allergen
Background: Major allergens of oilseed rape (OSR) pollen with molecular weights of 6/8, 14 and between 27 and 69 kD have been described. The aim of the present study was to further characterize the 14-kD allergen. Methods: The 14-kD protein was purified from OSR pollen extracts by poly-(L-proline) (PLP)-Sepharose affinity chromatography and characterized immunologically by means of allergic patients’ IgE antibodies, profilin-specific rabbit antisera, Western blot and ELISA inhibition using recombinant birch profilin (rBet v 2), and skin prick testing. Results: By PLP affinity chromatography, OSR pollen profilin was purified as a single protein of 14.5 kD and further identified as a profilin by three polyclonal rabbit antisera raised against ragweed and tobacco pollen profilin and the C-terminus of birch profilin. IgE binding of a human serum pool (n = 15) and four profilin-reactive sera to nitrocellulose-blotted OSR profilin was completely inhibited by 1 µg/ml rBet v 2 (birch profilin). Reciprocal ELISA inhibition using increasing concentrations of rBet v 2 and purified OSR profilin, respectively, showed that rBet v 2 strongly inhibits antibody binding to OSR profilin, whereas almost 100 times the amount of OSR profilin was needed to inhibit IgE binding to rBet v 2. Skin prick tests were positive (wheal ≧3 mm) with 5 µg/ml rBet v 2 in all three patients tested, and with OSR profilin in two patients at a concentration of 50 µg/ml. Conclusions: OSR pollen profilin shares IgE and IgG epitopes with Bet v 2 and other plant profilins and may represent a potentially relevant allergen for profilin-sensitized patients.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.