Proliferative responses towards native, heat-denatured and pepsin-treated ovalbumin by peripheral blood mononuclear cells from patients with hen's egg-sensitive atopic dermatitis

Abstract

In order to clarify the mechanism of food-antigen recognition, the proliferative responses of peripheral blood mononuclear cells (PBMCs) to native, heat-denatured or pepsin-treated ovalbumin (OA) were investigated in 16 hen's egg-sensitive patients with atopic dermatitis (AD). Seven of them had hypersensitivity to boiled hen's egg and others had not. The responses of PBMCs to heat-denatured OA were lower than those to native OA in the patients without hypersensitivity to boiled hen's egg. However, there were no differences of the responses of PBMCs between heat-denatured OA and native OA in the patients with hypersensitivity to boiled hen's egg. Moreover, the reduction of the responses of PBMCs to pepsin-treated OA was recognized in six out of seven patients. The primary structure of OA did not change by heating or pepsin treatment according to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). These results suggested that the secondary structure of OA changed in connection with the reduction of the responses of PBMCs to denatured OA. In addition, we demonstrated the suppressive effect of anti-HLA-DR and anti-HLA-DQ monoclonal antibodies on the proliferative response of PBMCs to OA. The results suggested that the proliferative responses of PBMCs to OA were restricted by HLA-DR or HLA-DQ in hen's egg-sensitive patients with AD.

Tandem Ion Exchange Fractionation of Chicken Egg White Reveals the Presence of Proliferative Bioactivity

“…The control experiment was repeated three times and determined to have no effect on cell proliferation. This is consistent with other studies that have used different cell lines and showed no proliferation response after treatment with ovalbumin. − …”

Effect of heat treatment and enzymatic digestion on the B cell epitopes of cow's milk proteins

“…Our findings suggest that new solid phase immunosolvent assays or in vitro histamine release assays using heat treated and/or digested food proteins may provide further information on food hypersensitivity, especially in children with IgE specific to food proteins. In fact, the use of enzyme‐digested egg proteins in patients with egg allergy is useful for predicting clinical symptoms or their resolution [45, 46]. Using heat treatment in addition to enzymatic digestion may improve the diagnostic value of this kind of assay.…”

Antibodies with specificity for native and denatured forms of ovalbumin differ in reactivity between enzyme‐linked immunosorbent assays

“…Moreover, OVA is an often used model antigen for immunological studies and several studies have characterized epitopes on the protein, e.g. in relation to allergy . OVA is a serpin (serin protease inhibitor), belonging to a large protein family, the members of which undergo structural changes upon protease binding .…”