Adsorption of Isotype “E” Antibodies on Affinity Magnetoliposomes

Abstract

The performance of affinity magnetoliposomes (AML) to adsorb specific “E” isotype antibodies from a previously characterized pool of allergic patients sera is described. Magnetoliposomes (ML) were prepared by enrobing nanometer‐sized colloidal magnetite particles with a phospholipid bilayer composed of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE). The latter lipid type was used to covalently anchor antigenic proteins, present in an extract of Dermathophagoids pteronyssinus and Blomia tropicalis mites. In this way, so‐called AML were produced. In the generation process of AML, the capacity of ML to couple antigenic proteins is first described as a func‐tion of the allergenic extract type, and, secondly as a function of the phosphatidylethanolamine content in the outer layer of the lipidic coat. Adsorption of antibodies onto the AML was checked in a high‐gradient magnetophoresis system that consists of a packed capillary column in which the AML were first magnetically captured on stainless steel fibers, and which were subsequently overflowed either with sera of healthy individuals or with a pool of sera from allergic patients. The performance of the magnetic biocolloidal adsorber and the selectivity of the liposome‐based adsorbent were characterized by a frontal analysis in capillary column and constructed breakthrough curves. The results show a 100% selectivity for adsorption of specific IgE (IgE antibodies generated by hypersensitivity reactions in humans with respiratory allergies), suggesting the unique potentialities of AML in the diagnosis of allergic symptoms.

Keywords:

• Magnetoliposomes
• Immunoglobulin E
• Dermathophagoids pteronyssinus
• Blomia tropicalis