Biomedical subjects

Hari M Vijay

Publications and source records attributed to Hari M Vijay.

4 recordsLinked to original sources

PubMed2006

Detection of recombinant Alt a1 in a two-site, IgM based, sandwich ELISA opens up possibilities of developing alternative assays for the allergen.

Alternaria alternata is well known to induce IgE-mediated asthma in humans. Alt a1, a 29 kD glycoprotein doublet composed of 14.5 and 16 kD subunits, is the major allergen of this mould. Detection of Alt a1 relies on a two-site sandwich ELISA using the same IgG subclass immunoglobulin as primary and secondary antibody. In this study, we have compared two IgM monoclonal antibodies against recombinant and native Alt a1 in detecting the allergen in a two-site sandwich ELISA. Although both IgM clones detected the native and the recombinant allergen by SDS-PAGE immunoblotting and by the antibody-capture ELISA, only the IgM against recombinant Alt a1 was able to detect the corresponding, and not the native allergen, in a two-site sandwich ELISA. The IgM against native Alt a1 was unable to detect either allergen by this method. A combination of the two IgM clones and with a commercially available IgG failed to detect both allergens. However, atopic human IgE detected both forms of the allergen with the two IgM clones as primary antibody. This is the first time to demonstrate detection of Alt a1 in a two-site, IgM based, sandwich ELISA opening up possibilities for exploring novel detection methods, based on this approach.

Allergens↗

PubMed2005

Isolation and characterization of a cDNA clone encoding one IgE-binding fragment of Penicillium brevicompactum.

BACKGROUND: The abundance of allergenic Penicillium species has been associated with an increased incidence of childhood asthma and pulmonary bleeding. Penicillium brevicompactum has been identified as the most prevalent indoor species of this genus. However, detailed studies on the allergens of the ubiquitous Penicillium species are still lacking. For the characterization of allergens of prevalent Penicillium species, molecular cloning of the allergen genes of P. brevicompactum was performed in the present study. METHODS: A phage cDNA library of P. brevicompactum was constructed in Uni-ZAP XR vector using mRNA isolated from the organism. The cDNA library of P. brevicompactum was screened using pooled atopic sera. RESULTS: Screening of P. brevicompactum cDNA library resulted in one positive clone encoding an estimated molecular weight of 11 kDa polypeptide, rich in acidic residues (>20%), with a pI of 3.87. This clone was designated as Pen b 26 and found to be reactive only against the atopic sera obtained from individuals sensitive to P. brevicompactum. The amino acid sequence analysis of Pen b 26 revealed that it had strong homology to the 60S acidic ribosomal protein P1 family from different eukaryotic sources, predominantly fungal aero-allergens. Other features of Pen b 26 including having high alpha-helical content (>50%), alanine-rich residues (>20%), and a well-conserved C-terminal epitope region fits well into the common properties of 60S acidic ribosomal proteins. CONCLUSIONS: The results obtained suggest that the allergenic clone, Pen b 26 is a 60S acidic ribosomal protein P1 of P. brevicompactum and shows strong similarity to other P1 family proteins.

Amino Acid Sequence↗

PubMed2004

Fungal allergens.

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Air Pollutants↗

PubMed2003

IgE binding synthetic peptides of Alt a 1, a major allergen of Alternaria alternata.

Alternaria alternata protein, Alt a 1 is a major allergen associated with allergy in atopic patients. Although the molecule binds strongly to IgE antibody from patients, the epitopes involved have not been identified or defined. In the present study, we synthesized overlapping peptides spanning the whole sequence and evaluated their IgE binding with sera from patients with Alternaria-induced allergy. The results identified four IgE binding linear regions. Two of these regions K41-P50 and Y54-K63 showed consistent reactivity with all four patients studied. The specific epitopes involved in the immune response may be of value in the immunodiagnosis and probably also in specific immunotherapy.

Allergens↗