Enzymatic activity of Dermatophagoides pteronyssinus extracts after acidic treatment.
BACKGROUND
Mite extracts contain potent enzymes. These enzymes, especially Der p 1, may affect the bronchial homeostasis and the amplification of the allergic response. The objectives of this study were to determine how depigmentation affects the enzymatic activity of allergen extracts of Dermatophagoides pteronyssinus and to verify if these depigmented extracts retain their in vitro allergenic properties.


METHODS
Four native extracts were manufactured from 4 different batches of raw material of D. pteronyssinus. Once extracted, native extracts were reconstituted and modified by adding increasing quantities of 2 M HCl to the solution and dialyzed against double-distilled water. The enzymatic activity of these 8 extracts (4 native and 4 depigmented) was evaluated using in vitro methods. The allergenic potency was evaluated by human specific IgE and IgG ELISA inhibition experiments. The major allergen content (Der p 1 and Der p 2) was measured with monoclonal antibodies.


RESULTS
Protease, phosphatase, lipase and glycosidase activity was detected in native extracts. After depigmentation, all the enzymatic activities showed a significant decrease. SDS-PAGE reveals the same protein profile in both types of extracts. The results of ELISA inhibition confirmed that depigmented extracts preserved their antigenic and allergenic capacity. Der p 2 levels increased in depigmented extracts, while the detection capacity of Der p 1 decreased.


CONCLUSIONS
The depigmentation process significantly reduced the enzymatic activity of these mite extracts, while preserving their allergenicity and antigenicity. No significant differences were observed in the antigenic profile of native and depigmented extracts.
Fernández-Caldas
Enrique
E
Research and Development, Laboratories LETI, Madrid, Spain.
Gallego
Mayte
M
Carnés
Jerónimo
J
Iraola
Victor
V
D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology / Q000378:metabolism; D060829:Arthropod Proteins; D003546:Cysteine Endopeptidases; D040002:Dermatophagoides pteronyssinus / Q000201:enzymology* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006851:Hydrochloric Acid; D006863:Hydrogen-Ion Concentration; D014020:Tissue Extracts / Q000276:immunology / Q000502:physiology*
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C451163:Dermatophagoides pteronyssinus antigen p 2; D014020:Tissue Extracts; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1; D006851:Hydrochloric Acid