Staines N A, Harper N, Ward F J, Malmström V, Holmdahl R, Bansal S
Infection and Immunity Research Group, Division of Life Sciences, Kings College, London, UK.
Clin Exp Immunol. 1996 Mar;103(3):368-75. doi: 10.1111/j.1365-2249.1996.tb08289.x.
The purpose of the study was to map the dominant T cell epitope of the CB11 sequence of CII in RTlu haplotype rats and to determine if, when used as a synthetic peptide, it would induce tolerance to protect against CIA. A dominant epitope corresponding to residues 184-198 included in the sequence of the CB11 fragment of bovine CII was identified in proliferation assay using peptides in an epitope scanning system using synthetic peptides of 15 amino acids, overlapping by 12 amino acids. This epitope is bovine-specific, but cross-reacts with the corresponding rat peptide. Minor epitopes in the bovine CB11 sequence was also autoantigenic. Use of independently synthesized and purified 184-198 peptide confirmed its dominance in the T cell responses of arthritic rats. The peptide itself was not arthritogenic. Cells from lymph nodes draining arthritic feet were particularly responsive to the dominant peptide sequence, and showed evidence of epitope spreading to include reactions to at least four subdominant epitopes. Mucosal tolerance was successfully induced by instilling CII into the nose of rats before induction of CIA: this was found to delay the onset of disease, reduce mean disease severity, shift the anti-CII antibody response to favour antibodies of the IgG1, rather than the IgG2b isiotype, and to reduce T cell reactivity to both CII and to the 184-198 peptide. The dominant 184-198 peptide itself had the same tolerogenic effects when given nasally to rats daily, on the 4 days immediately preceding the induction of CIA. Two forms of CIA with acute and delayed disease onset were each modified by pre-treatment with the peptide. This study demonstrates that mucosal tolerance to CII can be induced by delivering it nasally in a way similar to that achieved previously by oral delivery, and that the use of an immunodominant epitope contained in a synthetic peptide will also suppress the immunologic and arthritic responses to collagen.
本研究的目的是绘制RTlu单倍型大鼠中Ⅱ型胶原（CII）的CB11序列的主要T细胞表位，并确定当用作合成肽时，它是否会诱导耐受性以预防胶原诱导的关节炎（CIA）。在使用15个氨基酸且重叠12个氨基酸的合成肽的表位扫描系统中，通过增殖试验，在牛CII的CB11片段序列中鉴定出了对应于184 - 198位残基的主要表位。该表位是牛特异性的，但与相应的大鼠肽发生交叉反应。牛CB11序列中的次要表位也具有自身抗原性。使用独立合成和纯化的184 - 198肽证实了其在关节炎大鼠T细胞反应中的主导地位。该肽本身不具有致关节炎性。来自患有关节炎足部引流淋巴结的细胞对主要肽序列特别敏感，并显示出表位扩展的证据，包括对至少四个次主导表位的反应。在诱导CIA之前，通过向大鼠鼻腔内滴注CII成功诱导了黏膜耐受性：发现这延迟了疾病的发作，降低了平均疾病严重程度，使抗CII抗体反应转向有利于IgG1型抗体而非IgG2b亚型抗体，并降低了T细胞对CII和184 - 198肽的反应性。在诱导CIA前的4天，每天给大鼠鼻腔内给予主要的184 - 198肽本身时，也具有相同的耐受性作用。两种具有急性和延迟疾病发作形式的CIA均通过肽预处理得到了改善。本研究表明，通过鼻腔给药可以诱导对CII的黏膜耐受性，其方式类似于先前通过口服给药所实现的方式，并且使用合成肽中包含的免疫显性表位也将抑制对胶原蛋白的免疫和关节炎反应。
