A New Approach to Assess the Retention of Allergen (Der f 1 and Der p 1) on Anionic and Nonanionic Cotton Bedding Sheets After a Vigorous Sequential Cleaning Regime as Assessed by ELISA

Abstract

Anionic surfaces can interact with a variety of biological molecules and when used on bedding material may have the potential of binding with and sequestering protein allergens such as those produced by dust mites. However, no method exists to evaluate the efficacy of this claim. The purpose of this study was to develop a method using enzyme-linked immunosorbent assay (ELISA) to evaluate the capability of anionic treated cotton bedding sheet material to retain medically important dust mite allergens in direct comparison with nonanionic cotton bedding sheet material from a single manufacturer. Anionic, and nonanionic cotton bedding sheets were challenged singularly with water suspended pulverized dust mite Dermatophagoides farinae, water suspended pulverized dust mite D. pteronyssinus, or water alone as a negative control. All dried inoculums were subjected to four sequential extraction series using water in the first two separate extractions and water with surfactant in the last two separate extractions. All four extractions were assessed by ELISA using monoclonal antibodies specific for medically important protein allergens Der f 1 (D. farinae) or Der p 1 (D. pteronyssinus), respectively. There were a total of 25 replicates for each assessment. Our findings demonstrate that nearly all of the Der f 1 and Der p 1 was released from the nonanionic fabric after the first water extraction. Conversely, most of the Der f 1 and Der p 1 allergens were retained by the anionic fabric after both water extractions and was released only after surfactant was used. Our data indicated that >80% of Der f 1 and Der p 1 was released from the nonanionic fabric after the initial two water extractions while 80% of Der f 1 and Der p 1 was retained by anionic fabric after the same extractions. The method proved to be robust and data was reproducible. Protein extraction using less stringent to high stringent conditions demonstrated the effectiveness of anionic fabric in retaining dust mite proteins that cause allergy. This method can be used to assess other materials while allergists should consider the use of anionic bedding as it effectively retained dust mite allergens Der f 1 and Der p 1 until laundering can remove them from the household.