Bungy G A, Rodda S, Roitt I, Brostoff J
Department of Immunology, University College London Medical School, GB.
Eur J Immunol. 1994 Sep;24(9):2098-103. doi: 10.1002/eji.1830240925.
Rye grass is the major cause of hay fever which currently affects 20% of the population. Lolium perenne group I (Lol p I) is a glycoprotein of 240 amino acid residues, representing the main allergen of rye grass. We have used peripheral blood mononuclear cells (PBMC) from controls and subjects allergic to rye grass and cultured them with L. perenne extract (LPE) and Lol p I and measured lymphocyte activation using thymidine incorporation. Patients were further studied against the 115 overlapping peptides of the iso-allergen clone 5A of Lol p I to see whether the 4 amino acid residue differences between clone 1A and clone 5A affect the T cell epitope and thus, lymphocyte activation. There are 24 peptide differences between isoallergen clone 1A and clone 5A occurring in pools 4, 13, 16 and 19 each one of which could be an immunodominant epitope. The PBMC from all allergic patients studied showed a strong proliferative response to LPE and Lol p I. Five immunogenic peptide pools, pool 6, 15, 16, 17 and 19 of the isoallergen clone 5A were also identified. Most of these pools are in the C-terminal region of Lol p I. Out of 20 pools tested in vitro 1 pool (pool-17) induced PBMC proliferation in five out of six patients who were not restricted to an HLA class II DR gene product. However, three out of the six subjects responded to various other peptide pools in addition to the immunodominant pool. In spite of the amino acid differences between the two clones, pool 17 still remains the immunodominant T cell epitope. Control subjects showed only weak responses to LPE and no detectable response to either Lol p I or peptide pools. From within the most active pool we have defined two peptides of the isoallergen clone 5A (identical in sequence with clone 1A) which stimulate lymphocytes from rye grass-sensitive patients in vitro. Previous studies with the two continuous sequences (193WGAVWRIDTPDK204 and 195AVWRIDTPDKLT206) tested in vivo by intradermal skin testing have shown typical delayed-type hypersensitivity reactions after 24-48 h in one patient. Comparison of amino acid sequences of Lol p I, Lol p II and Lol p III proteins revealed a significant level of structural similarity among them. Interestingly, 50% of the residues of the second peptide sequence are also present in Lol p II and Lol p III.(ABSTRACT TRUNCATED AT 400 WORDS)
黑麦草是花粉热的主要病因，目前影响着20%的人口。多年生黑麦草I组（Lol p I）是一种由240个氨基酸残基组成的糖蛋白，是黑麦草的主要过敏原。我们使用了来自对照组和对黑麦草过敏的受试者的外周血单核细胞（PBMC），并用多年生黑麦草提取物（LPE）和Lol p I对其进行培养，通过胸腺嘧啶核苷掺入法测量淋巴细胞活化情况。我们进一步研究了患者对Lol p I的同种过敏原克隆5A的115个重叠肽段，以观察克隆1A和克隆5A之间的4个氨基酸残基差异是否会影响T细胞表位，进而影响淋巴细胞活化。同种过敏原克隆1A和克隆5A在第4、13、16和19组中存在24个肽段差异，每个差异肽段都可能是免疫显性表位。所有研究的过敏患者的PBMC对LPE和Lol p I均表现出强烈的增殖反应。还鉴定出了同种过敏原克隆5A的5个免疫原性肽组，即第6、15、16、17和19组。这些肽组大多位于Lol p I的C末端区域。在体外测试的20个肽组中，有1个肽组（第17组）在6名患者中的5名患者中诱导了PBMC增殖，这些患者不限于HLA II类DR基因产物。然而，6名受试者中有3名除了对免疫显性肽组有反应外，还对其他各种肽组有反应。尽管两个克隆之间存在氨基酸差异，但第17组仍然是免疫显性T细胞表位。对照组受试者对LPE仅表现出微弱反应，对Lol p I或肽组均未检测到反应。从最活跃的肽组中，我们确定了同种过敏原克隆5A的两个肽段（与克隆1A序列相同），它们在体外刺激对黑麦草敏感患者的淋巴细胞。先前对这两个连续序列（193WGAVWRIDTPDK204和195AVWRIDTPDKLT206）进行皮内皮肤试验的体内研究表明，一名患者在24 - 48小时后出现了典型的迟发型超敏反应。Lol p I、Lol p II和Lol p III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。有趣的是，第二个肽序列的50%的残基也存在于Lol p II和Lol p III中。（摘要截选至400字）
