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See detailAnalysis of the allergenicity of natural and recombinant Der p 3
Bouaziz, Ahlem ULg; Campisi, vincent; Herman, julie et al

Poster (2012, June 19)

Background: Der p 3 a trypsin-like protease is a Dermatophagoides pteronyssinus allergen which is synthesized in the mite under a zymogen form. The enzymatic activity of this allergen has been shown to ... [more ▼]

Background: Der p 3 a trypsin-like protease is a Dermatophagoides pteronyssinus allergen which is synthesized in the mite under a zymogen form. The enzymatic activity of this allergen has been shown to enhance the inflammatory process of allergy. To date, there are a few studies that described the allergenicity and the IgE reactivity of the group 3 allergens, the allergenic properties of recombinant Der p 3 was also not characterized. Methods: The autolysis of rDer p 3 and rDer p 3 S196A were analyzed by means of SDS-PAGE and enzymatic activity and their allergenicities by means of assays for IgE binding, IgE binding inhibition and basophiles mediator-release. Results: 100% of the sera from allergic patients showed IgE reactivity to natural Der p 3 and recombinant form. However, the IgE binding to the Der p 3 was less 4 times than rDer p 1. The IgE binding to rDer p 3 S196A was higher than rDer p 3. These variations can be linked with the phenomen of autolysis and instability of Der p 3 during the ELISA test. The mediators release performed with RBL sensitized with sera from allergic patients and stimulated with rDer p3, rDer p 3 S196A and natural Der p 3 were similar and lower than Der p 1 for concentration < 10 ng/ml. Conclusions: recombinant mature Der p 3 retained overall identity to its natural form in terms of structure and allergenicity. The instability and autolysis of Der p 3 drastically influence its IgE binding capacity. These results can be explain the considerable variations with the frequencies reactivity (16-100%) of natural Der p 3. The RBL assays demonstrated that the allergenicity of rDer p 3 is similar to rDer p 1 for the concentrations >10 ng /ml. [less ▲]

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See detailActivation mechanism of recombinant Der p 3 allergen zymogen - Contribution of cysteine protease Der p 1 and effect of propeptide glycosylation
Dumez, Marie-Eve ULg; Teller, Nathalie; Mercier, Frédéric ULg et al

in Journal of Biological Chemistry (2008), 283(45), 30606-30617

The trypsin-like protease Der p 3, a major allergen of the house dust mite Dermatophagoides pteronyssinus, is synthesized as a zymogen, termed proDer p 3. No recombinant source of Der p 3 has been ... [more ▼]

The trypsin-like protease Der p 3, a major allergen of the house dust mite Dermatophagoides pteronyssinus, is synthesized as a zymogen, termed proDer p 3. No recombinant source of Der p 3 has been described yet, and the zymogen maturation mechanism remains to be elucidated. The Der p 3 zymogen was produced in Pichia pastoris. We demonstrated that the recombinant zymogen is glycosylated at the level of its propeptide. We showed that the activation mechanism of proDer p 3 is intermolecular and is mediated by the house dust mite cysteine protease Der p 1. The primary structure of the proDer p 3 propeptide is associated with a unique zymogen activation mechanism, which is different from those described for the trypsin-like family and relies on the house dust mite papain-like protease Der p 1. This is the first report of a recombinant source of Der p 3, with the same enzymatic activity as the natural enzyme and trypsin. Glycosylation of the propeptide was found to decrease the rate of maturation. Finally, we showed that recombinant Der p 3 is inhibited by the free modified prosequence TP1R. [less ▲]

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See detailApolipoprotein L-1 Promotes Trypanosome Lysis By Forming Pores In Lysosomal Membranes
Perez-Morga, David; Vanhollebeke, Benoit; Paturiaux-Hanocq, Françoise et al

in Science (2005), 309(5733), 469-72

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a ... [more ▼]

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a membrane-addressing domain. In lipid bilayer membranes, apolipoprotein L-I formed anion channels. In Trypanosoma brucei, apolipoprotein L-I was targeted to the lysosomal membrane and triggered depolarization of this membrane, continuous influx of chloride, and subsequent osmotic swelling of the lysosome until the trypanosome lysed. [less ▲]

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See detailApolipoprotein L-I is the trypanosome lytic factor of human serum.
Vanhamme, Luc; Paturiaux-Hanocq, Francoise; Poelvoorde, Philippe et al

in Nature (2003), 422(6927), 83-7

Human sleeping sickness in east Africa is caused by the parasite Trypanosoma brucei rhodesiense. The basis of this pathology is the resistance of these parasites to lysis by normal human serum (NHS ... [more ▼]

Human sleeping sickness in east Africa is caused by the parasite Trypanosoma brucei rhodesiense. The basis of this pathology is the resistance of these parasites to lysis by normal human serum (NHS). Resistance to NHS is conferred by a gene that encodes a truncated form of the variant surface glycoprotein termed serum resistance associated protein (SRA). We show that SRA is a lysosomal protein, and that the amino-terminal alpha-helix of SRA is responsible for resistance to NHS. This domain interacts strongly with a carboxy-terminal alpha-helix of the human-specific serum protein apolipoprotein L-I (apoL-I). Depleting NHS of apoL-I, by incubation with SRA or anti-apoL-I, led to the complete loss of trypanolytic activity. Addition of native or recombinant apoL-I either to apoL-I-depleted NHS or to fetal calf serum induced lysis of NHS-sensitive, but not NHS-resistant, trypanosomes. Confocal microscopy demonstrated that apoL-I is taken up through the endocytic pathway into the lysosome. We propose that apoL-I is the trypanosome lytic factor of NHS, and that SRA confers resistance to lysis by interaction with apoL-I in the lysosome. [less ▲]

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