ESTIMATION OF DER-PI AND DER-FI QUANTITIES IN THE REFERENCE PREPARATIONS OF DERMATOPHAGOIDES MITE EXTRACTS

A monoclonal antibody-based enzyme-linked immunosorbent assay (MoAb-ELISA) was developed to measure the major Dermatophagoides mite allergens, Der pI and Der fI. The assay was highly species-specific and sensitive. Using this assay system, the absolute mass unit of Der pI and Der fI in the reference preparations of the extracts was estimated. The primary standards used were the purified Der pI and Der fI preparations. The reference preparations of the D. pteronyssinus and D. farinae extracts (92-Dp and 92-Df), which had been prepared from the same amount of mite bodies of both species, were found to contain the same levels of the Der I allergens, 10.1 mu g/ml of Der pI and 10.0 mu g/ml of Der fI, respectively. A histamine release assay with leucocytes from mite-allergic donors showed that the total allergenic potency of 92-Dp and 92-Df was comparable. This result indicates that the estimated Der I levels in these extracts seem to be valid, at least, in the balanece between the two species, although further comparisons of the absolute quantities by several different laboratories are needed. The Der I levels in the WHO/IUIS international reference preparation of D. pteronyssinus and the CBER standard mite extracts, E4-Dp and ES-Df, were also estimated using this assay system. They were found to contain 4.4 mu g/vial and 13.3 mu g/ml of Der pI and 9.5 mu g/ml of Der fI, respectively.