Human T cell responses to recombinant mite antigens of Dermatophagoides farinae

Background: The IgE-binding peptides Mag 1 and Mag 3 and the high-molecular-weight protein M-177 have been identified as parts of the apolipophorin-like group 14 house dust mite allergen. By analogy with the homologous insect proteins, apolipophorins are hydrophobic proteins found in lipid bodies and lipid transport particles. This explains why they degrade and are poorly represented in extracts. Methods: We have examined the T cell stimulation induced by a 341-residue recombinant Der p 14 peptide equivalent to the Mag 1 polypeptide examined by others. Results: Peripheral blood mononuclear cells from both allergic and non-allergic donors responded strongly in in vitro proliferation assays to the Der p 14 peptide to induce markedly more ³H-thymidine incorporation than Der p 2 and the release of Th2 cytokines. Conclusions: The apolipophorin-like group 14 allergens, despite their predicted hydrophobicity and lipid-binding activity, can induce high IgE responses and T cell stimulation. They appear to be important mite allergens unsuited to representation by aqueous extracts of mites.

Section: Discussionsupporting

confidence: 51%

“…The ability of the recombinant polypeptide fragments Mag 1 and Mag 3 to stimulate the proliferation of T cells from peripheral blood mononuclear cells was examined by Fujii et al [6]. Their initial test showed that only Mag 3 appeared stimulatory so this was examined further.…”

Section: T-cell Responses To Group 14 Allergensmentioning

confidence: 99%

Sensitisation to the Lipid-Binding Apolipophorin Allergen Der p 14 and the Peptide Mag-1

Epton¹,

Dilworth²,

Smith³

et al. 2001

“…The ability of recombinant Der f 2, Der f 10 and Mag 1, 3 (fragments of Der f 14) to stimulate T-cell proliferation was compared [74]. The responses to the high IgE-binding allergens Der f 2 and Mag 3 peptide were high and the responses to Mag 1 and Der f 10 were low.…”

Section: T-cell Responses To Purified Allergensmentioning

confidence: 99%

“…The peptide, Mag 3, which was an arbitrary fragment expressed from a partial cDNA clone from D. farinae, was shown to be a part of a 177,000 MW allergen with the same strength of reactivity as Der f 1 and 2 in both IgE-binding and T-cell assays [49, 74]. The high-molecular-weight protein did not contain lipid or carbohydrate moieties and the staining of histological section showed it was distributed throughout the body [49].…”

Section: Group 14 Allergensmentioning

confidence: 99%

Characterization and Immunobiology of House Dust Mite Allergens

Thomas¹,

Smith²,

Hales³

et al. 2002

304

254

The examination of house dust mite extracts has indicated that over 30 different proteins can induce IgE antibody in patients allergic to the house dust mite. There are however dominant specificities especially the group 1 and 2 allergens which can account for much of the allergenicity of extracts. Of the 19 denominated allergens, the major IgE binding has been reported for the group 1, 2, 3, 9, 11, 14 and 15 allergens. The high-molecular-weight group 11, 14 and 15 allergens have only recently been described and although high IgE binding has been anticipated from immunoblotting, there is a need for considerable corroboration. Similarly, the study of the group 3 and 9 serine protease allergens has been incomplete. The group 4, 5, 7 and 8 allergens have shown intermediate IgE binding and the group 10 tropomyosins are of interest because of their potential cross-reactivity with allergen from disparate species. Although the progress with the production of recombinant group 1 allergens has been recent, many of the allergens can be produced as high IgE-binding polypeptides. The tertiary structure of the group 2 allergens has been determined from recombinant proteins and they are an excellent model for the investigation of modified allergens. An unexpected property of the group 1, 2 and 3 allergens has been the high degree of polymorphism found by cDNA analysis. It has however been possible to identify sequences to represent the variation in the natural allergens. The group 7 and 14 allergens show secondary modifications which vary in different extracts creating batch variation. While some estimate of the importance of allergens can be obtained from IgE binding, few analyses of T-cell responses have been made and these regulate both the development of, and the protection from sensitization.

“…This frequency and magnitude of binding was similar to the major allergen Der f 2. Moreover, T–cell–proliferative responses to Mag 3 were large and correlated with responses to Der f 2 [25]. …”

Section: Discussionmentioning

confidence: 99%

High–Molecular–Weight Allergens of the House Dust Mite: An Apolipophorin–Like cDNA Has Sequence Identity with the Major M–177 Allergen and the IgE–Binding Peptide Fragments Mag1 and Mag3

Epton

Dilworth

Smith

et al. 1999

Background: A 349–residue recombinant polypeptide of Dermatophagoides farinae, Mag 3, has been shown to represent part of a larger 177–kD (M–177) allergen with very high IgE–binding activity. Methods: Cloning and sequencing of cDNA from the house dust mites Dermatophagoides pteronyssinus and Euroglyphus maynei was used to characterise the polypeptide containing the Mag 3 sequence. Results: cDNA clones containing the complete sequence of the E. maynei homologue of the M–177 allergen were isolated and analysed. The translation contained not only an amino acid sequence with 90% identity to the 349–residue Mag–3 fragment but also a further sequence with 90% identity to another IgE–binding recombinant D. farinae polypeptide designated Mag 1. The complete sequence encoded a mature polypeptide of 1,650 residues and a molecular mass of 189.5 kD. cDNA clones from D. pteronyssinus also encoded sequences equivalent to the Mag 1 and 3 polypeptides. The M–177 sequence showed strong similarity to the lipid transport apolipophorins found in insect lipophorins. Conclusions: cDNA sequence data show that the D. pteronyssinus and E. maynei homologues of the M–177 high–molecular–weight D. farinae allergen contain sequences equivalent to both the Mag 1 and Mag 3 recombinant IgE–binding fragments. The N–terminal sequence of the full–length 1,650 amino–acid allergen showed strong similarity to the insect apolipophorins which are poorly soluble in aqueous extracts and exist in the lipid transport particles in haemolymph. It is proposed that presentation in lipid particles could be a factor which enhances the immunogenicity of this group of allergens.