Baskar S, Parronchi P, Mohapatra S, Romagnani S, Ansari A A
Johns Hopkins Asthma and Allergy Center, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224.
J Immunol. 1992 Apr 15;148(8):2378-83.
The in vitro proliferative response to purified allergens of the grass, Lolium perenne pollens was studied using PBMC from individuals allergic to grass pollens and Ag-specific T cell lines and T cell clones derived from them. The PBMC from all 10 subjects studied showed a strong response to Lol p I and most of them (8 of 10) also responded to Lol p III. Although Lol p II induced a moderate response in 4 of 10 individuals, it did not induce any response in others at all the Ag concentrations tested. However, one of the subjects (JH) responded to, besides Lol p I, both Lol p II and Lol p III equally well. Analysis of Ag-specific T cell lines and clones derived from three individuals showed varied pattern of reactivity to the Lol p allergens. Some of the Lol p III-specific T cell lines and clones were also stimulated by Lol p I and similarly, some of the Lol p I-specific T cell clones (derived from four other subjects) were stimulated by Lol p III; thus showing a two-way cross-reactivity between those T cells. In both cases, the cross-reactivity to Lol p II, when observed, was lower than that seen with Lol p I and Lol p III. Comparison of amino acid sequences of the three Lol p proteins revealed a significant level of structural similarity among them, including several segments of identical sequences. Although one of the synthetic peptides of Lol p III sharing appreciable sequence homology with other proteins stimulated PBMC from two subjects, three other peptides did not. Nevertheless, these studies indicated the possible existence of cross-reactive T cell epitope(s) among the grass pollen allergens. Based on these results, the relationship between amino acid sequence homology among the Lol p proteins and their recognition by T cells is discussed.
利用对草花粉过敏个体的外周血单核细胞（PBMC）以及从中衍生出的抗原特异性T细胞系和T细胞克隆，研究了对多年生黑麦草花粉纯化过敏原的体外增殖反应。所研究的10名受试者的PBMC对黑麦草花粉变应原1（Lol p I）均表现出强烈反应，其中大多数（10名中的8名）对黑麦草花粉变应原3（Lol p III）也有反应。虽然黑麦草花粉变应原2（Lol p II）在10名个体中的4名中诱导了中等反应，但在所有测试的抗原浓度下，其他个体对其根本没有反应。然而，其中一名受试者（JH）除了对Lol p I有反应外，对Lol p II和Lol p III的反应同样良好。对来自三名个体的抗原特异性T细胞系和克隆的分析显示，对Lol p过敏原的反应模式各不相同。一些Lol p III特异性T细胞系和克隆也受到Lol p I的刺激，同样，一些Lol p I特异性T细胞克隆（来自其他四名受试者）也受到Lol p III的刺激；因此表明这些T细胞之间存在双向交叉反应性。在这两种情况下，观察到的对Lol p II的交叉反应性低于对Lol p I和Lol p III的交叉反应性。对三种Lol p蛋白的氨基酸序列比较显示它们之间存在显著水平的结构相似性，包括几个相同序列的片段。虽然Lol p III的一种合成肽与其他蛋白具有相当的序列同源性，刺激了两名受试者的PBMC，但其他三种肽则没有。尽管如此，这些研究表明草花粉过敏原之间可能存在交叉反应性T细胞表位。基于这些结果，讨论了Lol p蛋白之间的氨基酸序列同源性与其被T细胞识别之间的关系。
