Cloning, expression, and analysis of the group 2 allergen from Dermatophagoides farinae from China

To obtain the recombinant group 2 allergen product of Dermatophagoides farinae (Der f 2), the Der f 2 gene was synthesized by RT-PCR. The full-length cDNA comprised 441 nucleotides and was 99.3 percent identical to the reference sequence (GenBank AB195580). The cDNA was bound to vector pET28a to construct plasmid pET28a(+)-Der f 2, which was transformed into E. coli BL21 and induced by IPTG. SDS-PAGE showed a specific band of about 14kDa in the hole cell lysate. s estiated by chroatography, about 3.86 g of the recobinant product as obtained, which conjugated with serum IgE from asthmatic children. The protein had a signal peptide of 17 amino acids. Its secondary structure comprised an alpha helix (19.86 percent), an extended strand (30.82 percent), and a random coil (49.32 percent). The subcellular localization of this allergen was predicted to be at mitochondria. Furthermore, its function was shown to be associated with an MD-2-related lipid-recognition (ML) domain. The results of this study provide a solid foundation for large-scale production of the allergen for clinical diagnosis and treatent of allergic disorders.

Com a finalidade de obter o produto recombinante do alergeno grupo 2 do Dermatophagoides farinae (Der f2), o gene Der f2 foi sintetizado por RT-PCR. O cDNA continha 441 nucleotídeos e era idêntico em 99,3 por cento à sequência de referência (GenBank AB195580). O cDNA foi ligado ao vetor pET28a para construir o plasmídeo pET28a(+)-Der f2, o qual foi introduzido por transformação em E. coli BL21 e induzido por IPTG. Em SDS-PAGE foi vista mia banda específica de 14 kDa no lisado celular. Conforme estimado por cromatografia, cerca de 3,86 mg do produto recombinante foi obtido, que reagia com IgE sérica de crianças asmáticas. A proteína continha um peptídeo sinal de 17 amino ácidos. Sua estrutura secundária consistia de uma alfa hélice (19,86 por cento), uma fita estendida (30,82 por cento), e uma sequência randômica (49,32 por cento). A localização subcelular desse alergeno foi predita ocorrer nas mitocôndrias. Sua função foi associada com o domínio de reconhecimento lipídico (ML) relacionado a MD-2. Os resultados desse estudo permitem a produção em larga escala do alergeno para o diagnóstico clínico e tratamento das doenças alérgicas.

Allergic contact dermatitis in the Asir region of Saudi Arabia: a pilot study

During the 16-month period from June 1993 to December 1994, 100 patients, Saudi nationals with suspected allergic contact dermatitis, were patch tested. True Test[TM], containing a routine series of 24 test substances, was used at the dermatology clinics in the Military Hospitals in Khamis Mushayt, Saudi Arabia. The results showed that 30% of the patients with suspected allergic contact dermatitis were sensitive to one or more chemical substances used in the patch test. Nickel was the most common allergen in female patients [17.3%] and chromium was the most common in male patients [10.4%]

An allergenic 2S storage protein from ricinus communis seeds which is a part of the 2s albumin precursor predicted by C-DNA data

A 1.9s albumin having allergenic activity and denoted Ric c III was isolated from an alcohol extract of defatted Ricinus communis seeds CB-1A, as a homogeneous protein by ion -exchange chromatography on SP-Sephadex, gel filtration on Sephadex G-75 and preparative polyacrylamide gel electrophoresis (6 mg Ric cIII/g CB-1A). The protein contained approximately 98 amino acid residues distributed in 2 chains of 67 anmd 34 residues, a molecular weight of 11.239 based on amino acid composition and pI=4.9 Ric c III can be aligned, on the basis of amino acid composition and partial amino acid sequence data, with residues 18 to 50 (51) and 66 to 130 of the 2S albumin precursor predicted by the cDNA data of S. D. Irwin, J. N. Ken, J. B. C. Findlary and J. M. Lord (Molecular and General Genetics, 222:400-408, 1990). The present data identify Ric c III as the second allergenic 2S storage albumin coded by this DNA