The chitinase allergens Der p 15 and Der p 18 from Dermatophagoides pteronyssinus.
BACKGROUND
House dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae cause allergic disease in humans as well as in dogs. In geographical regions where the two mite species coexist, they both elicit specific immunoglobulin (Ig E) responses in humans whereas dogs preferentially react to D. farinae extracts. In dogs the main IgE binding is directed to the D. farinae chitinase allergens Der f 15 and Der f 18 and not to the groups 1 and 2 allergens as found for humans. Although the IgE response of humans to Der f 18 has been investigated there is no report on Der f 15-specific IgE in humans.


OBJECTIVE
This study aimed to characterize the chitinase allergens Der p 15 and Der p 18 of D. pteronyssinus and to find out whether they are important allergens for humans.


METHODS
cDNA was cloned by a polymerase chain reaction strategy from D. pteronyssinus libraries using primers based on conserved chitinase sequences. IgE binding to the recombinant polypeptides was measured by immunosorbent assay. Mice were immunized with the polypeptides and cross-reactivity examined.


RESULTS
Two variants of Der p 15 were isolated, encoding mature proteins of 58.8 and 61.4 kDa. The amino acid sequences had 90% identity to Der f 15. The cDNA for Der p 18 encoded a mature protein of 49.2 kDa with 88% sequence identity to Der f 18. Der p 15-specific IgE was detected in 70% and Der p 18-specific IgE in 63% of a panel of 27 human allergic sera.


CONCLUSIONS
The D. pteronyssinus chitinases Der p 15 and Der p 18 show a high frequency of binding to IgE in allergic human sera. They are therefore potentially important allergens for humans as well as dogs.
O'Neil
S E
SE
Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, and Queensland Institute of Medical Research, Malaria and Scabies Laboratory, PO Royal Brisbane Hospital, Australia.
Heinrich
T K
TK
Hales
B J
BJ
Hazell
L A
LA
Holt
D C
DC
Fischer
K
K
Thomas
W R
WR
D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000235:genetics* / Q000276:immunology; D060829:Arthropod Proteins; D001483:Base Sequence; D016022:Case-Control Studies; D002688:Chitinases / Q000276:immunology*; D003001:Cloning, Molecular; D003429:Cross Reactions; D018076:DNA, Complementary / Q000032:analysis; D040002:Dermatophagoides pteronyssinus / Q000276:immunology*; D015723:Gene Library; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000276:immunology / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D018076:DNA, Complementary; C514374:Der p 15 allergen, Dermatophagoides pteronyssinus; C514375:Der p 18 allergen, Dermatophagoides pteronyssinus; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D002688:Chitinases