IN-VIVO BIOLOGICAL-ACTIVITY OF RECOMBINANT DER-P-II ALLERGEN OF HOUSE-DUST MITE

The cDNA coding for one of the major allergens of Dermatophagoides pte ronyssinus, Der p II, has been cloned and expressed in Escherichia col i as a fusion protein with glutathione S-transferase, The recombinant material (r Der p II) was tested in the skin of house-dust allergic pa tients, and was found to be almost as active as the purified native al lergen (n Der p II) in stimulating immediate hypersensitivity reaction s. The positivity to r Der p II in these patients, who were selected f or their skin-test reactivity to house-dust extract (HDE) and whole mi te extract (WME), was over 60%, and 80% of their sera contained detect able IgE antibody against the recombinant allergen. The level of speci fic IgE antibody against r Der p II was a mean of 40% of that against WME in the sera of patients who were skin test positive to both allerg en preparations. In contrast to the house-dust allergic patients, none of a group of allergic patients whose clinical history did not implic ate house dust, and who were skin test negative to HDE or WME, were po sitive to r Der p II. Of interest was the observation that only 37% of a group of subjects who were skin test positive to HDE and WME, but w ho reported no clinical history of allergic disease upon natural expos ure to house dust, reacted to r Der p II. These results demonstrate th e biological activity of r Der p II, and indicate, in persons skin tes t positive to house-dust mite extract, an association between reactivi ty to Der p II and the manifestation of clinical symptoms.