Allergenic characterization of a novel allergen, homologous to chymotrypsin, from german cockroach.
OBJECTIVE
Cockroach feces are known to be rich in IgE-reactive components. Various protease allergens were identified by proteomic analysis of German cockroach fecal extract in a previous study. In this study, we characterized a novel allergen, a chymotrypsin-like serine protease.


METHODS
A cDNA sequence homologous to chymotrypsin was obtained by analysis of German cockroach expressed sequence tag (EST) clones. The recombinant chymotrypsins from the German cockroach and house dust mite (Der f 6) were expressed in Escherichia coli using the pEXP5NT/TOPO vector system, and their allergenicity was investigated by ELISA.


RESULTS
The deduced amino acid sequence of German cockroach chymotrypsin showed 32.7 to 43.1% identity with mite group 3 (trypsin) and group 6 (chymotrypsin) allergens. Sera from 8 of 28 German cockroach allergy subjects (28.6%) showed IgE binding to the recombinant protein. IgE binding to the recombinant cockroach chymotrypsin was inhibited by house dust mite chymotrypsin Der f 6, while it minimally inhibited the German cockroach whole body extract.


CONCLUSIONS
A novel allergen homologous to chymotrypsin was identified from the German cockroach and was cross-reactive with Der f 6.
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Kyoung Yong
KY
Jeong
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Mina
M
Son
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Jae Hyun
JH
Lee
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.
Chein Soo
CS
Hong
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea. parkjw@yuhs.ac.
Jung Won
JW
Park
Allergens; German cockroach; chymotrypsin