Van Hoeyveld E M, Escalona-Monge M, de Swert L F, Stevens E A
Department of Internal Medicine, University Hospital Gasthuisberg, Leuven, Belgium.
Clin Exp Allergy. 1998 Sep;28(9):1131-7. doi: 10.1046/j.1365-2222.1998.00381.x.
Milk hydrolysates, although frequently used as substitutes in cases of cow's milk allergy, show a reduced but never a complete abolishment of antigenicity and allergenicity.
Our purpose was to determine the lower molecular weight limit of peptides to elicit skin reactions and to bind IgE antibodies in vitro.
Using FPLC, an ultrafiltrated whey hydrolysate, was fractionated in different molecular weight fractions. Skin-prick tests were performed with the hydrolysate and its fractions in five cow's milk allergic children, and RAST inhibition tests were done using the serum of these children.
On the basis of the lowest extinction values between two peaks of the chromatogram, seven fractions with molecular weights between 15000 and 125 Da were obtained. Peptides of > 2600 Da elicited a clearly positive skin reaction and inhibited IgE-binding, while peptides of < 1400 Da did not give any positive skin reaction but were still able to inhibit to a small extent IgE-binding to the hydrolysate.
Our findings suggest that for skin reactivity peptides of > 1400 Da are needed. The minimal molecular mass for IgE binding in vitro appears to be situated between 1400 and 970 Da. Such peptides might be used to develop a safe formula for patients reacting to milk hydrolysates or even for tolerance induction.
尽管牛奶水解物在牛奶过敏病例中常被用作替代品，但其抗原性和致敏性有所降低，但从未完全消除。
我们的目的是确定引发皮肤反应并在体外结合IgE抗体的肽的最低分子量限度。
使用快速蛋白质液相色谱法（FPLC），将超滤的乳清水解物分离成不同分子量的组分。对5名牛奶过敏儿童用该水解物及其组分进行皮肤点刺试验，并用这些儿童的血清进行放射变应原吸附试验（RAST）抑制试验。
根据色谱图两个峰之间的最低吸光度值，获得了7个分子量在15000至125道尔顿之间的组分。分子量>2600道尔顿的肽引发明显的阳性皮肤反应并抑制IgE结合，而分子量<1400道尔顿的肽未产生任何阳性皮肤反应，但仍能在一定程度上抑制IgE与水解物的结合。
我们的研究结果表明，对于皮肤反应性而言，需要分子量>1400道尔顿的肽。体外IgE结合的最小分子量似乎位于1400至970道尔顿之间。此类肽可用于为对牛奶水解物有反应的患者开发安全配方，甚至用于诱导耐受性。
