原标题：IgE和T细胞对草花粉第5组主要变应原Phl p 5的识别情况剖析
①梯牧草花粉主要过敏原Phl p 5是花粉热和哮喘最强的过敏原之一。②本研究对Phl p 5的免疫优势IgE-和T细胞识别位点进行了研究。③合成了7个肽段，P1 - P7全长31 - 38个氨基酸，跨越Phl p 5序列，采用圆二色谱法对其进行了表征，并对IgE反应活性、嗜碱性细胞活化和T细胞反应活性进行了测试。研究了载体结合肽诱导兔IgG抗体的能力，该抗体能识别不同草种的Phl p 5或交叉反应性变应原。检测肽特异性抗体抑制IgE对Phl p 5的反应活性的能力，以及在过敏患者由过敏原引起的嗜碱性细胞活化的能力。④肽段无二级结构，无IgE反应活性或相关致敏活性，表明Phl p 5 IgE表位具有构象性。除P3外，肽段特异性IgG抗体阻断了变态反应性和与温带禾草发生交叉反应的phlp5与IgE的结合。IgE抑制实验和分子建模在phlp5的N-和c -末端区域发现了几个聚集构象的IgE表位。P4在患者中刺激T细胞和细胞因子的反应最强，但不属于主要的IgE反应区域。⑤我们的研究显示了一个有趣的现象：Phl p 5中的IgE-和T细胞反应域是分离的，这为开发新的免疫疗法提供了基础，这种疗法可以选择性地针对IgE或T细胞的反应。
Dissection of the IgE and T-cell recognition of the major group 5 grass pollen allergen Phl p 5
The major timothy grass pollen allergen Phl p 5 belongs to the most potent allergens involved in hay fever and asthma.
This study characterized immune-dominant IgE- and T-cell–recognition sites of Phl p 5.
Seven peptides, P1 to P7 with a length of 31 to 38 amino acids that spanned the Phl p 5 sequence, were synthesized, characterized by circular dichroism spectroscopy, and tested for IgE reactivity, basophil activation, and T-cell reactivity. Carrier-bound peptides were studied for their ability to induce IgG antibodies in rabbits which recognize Phl p 5 or cross-reactive allergens from different grass species. Peptide-specific antibodies were tested for the capability to inhibit IgE reactivity to Phl p 5 and allergen-induced basophil activation of patients with allergy.
The peptides exhibited no secondary structure and showed no IgE reactivity or relevant allergenic activity, indicating that Phl p 5 IgE epitopes are conformational. Except for P3, peptide-specific IgG antibodies blocked IgE binding to Phl p 5 of patients with allergy and cross-reacted with temperate grasses. IgE inhibition experiments and molecular modeling identified several clustered conformational IgE epitopes on the N- as well as C-terminal domain of Phl p 5. P4, which stimulated the strongest T-cell and cytokine responses in patients, was not part of the major IgE-reactive regions.
Our study shows an interesting dissociation of the major IgE- and T-cell–reactive domains in Phl p 5 which provides a basis for the development of novel forms of immunotherapy that selectively target IgE or T-cell responses.
Margarete Focke-Tejkl Raffaela Campana Renate Reininger Christian Lupinek Katharina Blatt Peter Valent Tea Pavkov-Keller Walter KellerWalter KellerRudolf Valenta