Characterization of glutathione S-transferase from dust mite, Der p 8 and its immunoglobulin E cross-reactivity with cockroach glutathione S-transferase.
BACKGROUND
Sensitization to mite and cockroach allergens is common, and diagnosis and therapy of allergy can be further complicated by the presence of allergen isoforms and panallergens. Purified recombinant and native allergens are useful for studies to resolve such problems.


OBJECTIVE
To assess the allergenicity of native and recombinant mite glutathione S-transferase (GST) (Der p 8) and study the IgE cross-reactivity between Der p 8 and cockroach GST.


METHODS
Der p 8 cDNA encoding a new isoform was isolated and expressed in yeast. Native Der p 8 was affinity purified from mite extract. IgE reactivity to native and recombinant Der p 8 was assessed by ELISA using sera from allergic subjects from Taiwan, Singapore and Malaysia. IgE cross-reactivity between Der p 8 and cockroach GST was examined by IgE inhibition assays.


RESULTS
Our Der p 8 cDNA encoded a basic isoform (pI=8.5) containing six polymorphic residues located at positions 46, 106, 149, 160, 167 and 184. At least 8 isoforms of native Der p 8 were detected by two-dimensionalgel and immunoblot analyses. Sera from Taiwanese asthmatics showed 96% and 84% IgE reactivity to native Der p 8 and recombinant Der p 8, respectively. Native Der p 8 showed 75% and 65% IgE reactivity with sera from Malaysia and Singapore, respectively.


CONCLUSIONS
A high frequency of sensitization to mite GST among allergic subjects was observed but the titres of IgE reactivity were low. The IgE cross-reactivity between mite and cockroach GST suggests that GST is a panallergen.
Huang
C H
CH
Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Liew
L M
LM
Mah
K W
KW
Kuo
I C
IC
Lee
B W
BW
Chua
K Y
KY
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000937:Antigen-Antibody Reactions / Q000276:immunology; D039741:Antigens, Dermatophagoides; D052179:Antigens, Plant; D060829:Arthropod Proteins; D001249:Asthma / Q000276:immunology; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D003058:Cockroaches / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D040002:Dermatophagoides pteronyssinus / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005982:Glutathione Transferase / Q000276:immunology*; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology*; D007223:Infant; D020033:Protein Isoforms / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology
D000485:Allergens; D039741:Antigens, Dermatophagoides; D052179:Antigens, Plant; D060829:Arthropod Proteins; D018076:DNA, Complementary; C477068:Dermatophagoides pteronyssinus antigen p 8; D020033:Protein Isoforms; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D005982:Glutathione Transferase