Assessing the Impact of Lipids on the Allergenic Potential of Peanuts Using a Germ-Free Murine Model of Food Allergy

Rationale: Published studies have reported that lipid components in some foods interact with specific proteins to enhance their allergenicity. Peanuts have high lipid content and are potent allergenic sources with a number of allergenic proteins including the potent allergen Ara h 2. Therefore we compared clinical responses in mice sensitized with extracts of defatted and non-defatted peanut flour.

Methods: Extracts were prepared from defatted and non-defatted raw peanut flour. Protein concentrations were measured by Lowry Assay and Ara h 2 by immunoblotting. Germfree (GF) C3H/HeN mice were sensitized with defatted or non-defatted extracts by intraperitoneal injection (IP) each week with alum adjuvant. Mice were challenged (week 4) IP with 500 mg of Ara h 2 or peanut extract (without alum). Rectal temperatures were recorded and clinical scores assigned 30 minutes after challenge. Sera were collected for analysis of mMCP-1 and specific IgE.

Results: Ara h 2, the peanut allergen of interest was present in significant amounts in both defatted and non-defatted peanut extracts. Sensitized mice had statistically significant clinical reactions and temperature drops compared to controls.  However, differences in post-challenge clinical scores and reductions in body temperatures between sensitization groups were not statistically significant between the mice sensitized with full-fat vs. defatted peanut extracts.

Conclusions: In this study, defatting did not have a significant effect on the sensitization potential of peanut extracts of raw peanut as measured by challenges with peanut extract or Ara h 2 in GF mice. Future work will assess the impact of lipids on the sensitizing potential of roasted peanuts.