Radioallergosorbent test (RAST) studies with insolubilized polysaccharides

Area of Science:

• Immunology
• Mycology
• Allergy Research

Background:

• Fungal polysaccharides from Aspergillus fumigatus and Candida albicans are known to interact with human serum antibodies.
• These interactions involve complement fixation and precipitation, primarily with IgG, IgM, and IgA antibodies.

Purpose of the Study:

• To investigate the potential of modified fungal polysaccharides for detecting IgE antibodies.
• To evaluate a chemical insolubilization method for enhancing the use of fungal polysaccharides in allergy diagnostics.

Main Methods:

• Polysaccharide preparations from A. fumigatus and C. albicans were chemically modified using N-carboxyanhydride of L-leucine.
• The modified polysaccharides were tested for reactivity with human serum antibodies, including IgE, using the radioallergosorbent test (RAST).

Main Results:

• Chemical modification retained the reactivity of fungal polysaccharides with existing precipitins (IgG, IgM, IgA).
• The modified polysaccharides successfully detected specific IgE antibodies in sera from hypersensitive individuals, as shown by RAST.
• This indicates the presence of polysaccharide-specific IgE antibodies against A. fumigatus and C. albicans.

Conclusions:

• Chemically modified fungal polysaccharides are effective tools for detecting IgE antibodies.
• This method offers a novel approach for utilizing polysaccharides in RAST, particularly those difficult to couple to solid supports.
• The findings suggest a role for polysaccharide-specific IgE in hypersensitivity reactions to fungi like A. fumigatus and C. albicans.