Potter N T, Hashim G A, Day E D
J Immunol. 1986 Jan;136(2):516-20.
Synthetic peptide SP6 (RTPPPSG), comprising amino acid residues 98-103-Gly of myelin basic protein (MBP), and a series of peptide analogs were used to probe the structural requirements for antigenicity of a highly conserved region of a self protein. By means of a liquid-phase radioimmunoassay, antibody responses directed toward this determinant in both multi-specific anti-MBP and monospecific anti-peptide antisera were measured. The specificities of the antibodies present in the anti-MBP and anti-peptide antisera were examined by an equilibrium competitive inhibition radioimmunoassay by using the set of related peptides, as well as intact MBP from different species. Although the fine specificities of the reagent antisera differed, competitive inhibition analyses with intact MBP revealed a cross-reactive determinant involving residues 99-100 (Thr-Pro). This suggests that the neighborhood of the triprolyl region of MBP, despite its strong phylogenetic conservation, serves as an immunogen for humoral responses whether presented as a hapten-carrier conjugate or in the context of intact MBP. The latter supports the contention that the general antigenicity of a protein need not require sequence differences between the immunizing protein and its counterpart in the host.
合成肽SP6（RTPPPSG）由髓鞘碱性蛋白（MBP）的98 - 103位氨基酸残基-Gly组成，一系列肽类似物被用于探究自身蛋白高度保守区域抗原性的结构要求。通过液相放射免疫测定法，检测了多特异性抗MBP和单特异性抗肽抗血清中针对该决定簇的抗体反应。利用一组相关肽以及来自不同物种的完整MBP，通过平衡竞争抑制放射免疫测定法检测抗MBP和抗肽抗血清中存在的抗体的特异性。尽管试剂抗血清的精细特异性不同，但用完整MBP进行的竞争抑制分析揭示了一个涉及99 - 100位残基（苏氨酸-脯氨酸）的交叉反应决定簇。这表明，MBP的三脯氨酰区域附近，尽管其具有很强的系统发育保守性，但无论是作为半抗原-载体缀合物呈现还是在完整MBP的背景下呈现，都可作为体液反应的免疫原。后者支持了这样一种观点，即蛋白质的一般抗原性不一定要求免疫蛋白与其在宿主中的对应物之间存在序列差异。
