Seki J, Wang X, Ota A, Suzuki Y, Sakato N, Fujio H
Department of Immunochemistry, Osaka University.
J Biochem. 1992 Feb;111(2):259-64. doi: 10.1093/oxfordjournals.jbchem.a123746.
Three epitope peptides of hen egg-white lysozyme (HEL) were tested for ability to induce antibodies reactive with native HEL. Each peptide was coupled to bovine gamma-globulin (B gamma G) and 4 rabbits were immunized with each peptide-B gamma G conjugate in complete Freund's adjuvant. The mean association constants (K0s) of HEL-reactive antibodies (HEL-R-Abs) from each immunizing group to [3H]acetyl HEL or to [3H]acetyl-peptide were measured in solution by a double antibody method. Only peptide loop I.II (sequences 57-107 containing Cys64-Cys80 and Cys76-Cys94) induced high-affinity antibodies to HEL (K0 = 2.5 x 10(6)-2.3 x 10(7) M-1) among the three epitope peptides tested. The association constants of antipeptide loop I.II to [3H]acetyl peptide loop I.II were always one to two orders of magnitude higher than those to HEL. In addition, 50 to 80% of the anti-peptide loop I.II antibodies were reactive with native HEL. The specificity of anti-peptide loop I.II was directed to a conformational feature of the peptide rather than to native HEL and reactivity of the antibody to HEL was interpreted as a kind of cross-reaction. The HEL-R-Abs from anti-Ploop I.II antisera also manifested neutralizing activities against the enzymic activity of HEL when Micrococcus luteus was used as the substrate.
对鸡蛋清溶菌酶（HEL）的三种表位肽诱导与天然HEL发生反应的抗体的能力进行了测试。将每种肽与牛γ球蛋白（BγG）偶联，并用每种肽 - BγG偶联物在完全弗氏佐剂中免疫4只兔子。通过双抗体法在溶液中测量来自每个免疫组的HEL反应性抗体（HEL - R - Abs）与[³H]乙酰基HEL或与[³H]乙酰基肽的平均缔合常数（K₀s）。在所测试的三种表位肽中，只有肽环I.II（包含Cys64 - Cys80和Cys76 - Cys94的57 - 107位序列）诱导出对HEL的高亲和力抗体（K₀ = 2.5×10⁶ - 2.3×10⁷ M⁻¹）。抗肽环I.II与[³H]乙酰基肽环I.II的缔合常数总是比与HEL的缔合常数高1至2个数量级。此外，50%至80%的抗肽环I.II抗体与天然HEL发生反应。抗肽环I.II的特异性针对肽的构象特征而非天然HEL，并且该抗体与HEL的反应性被解释为一种交叉反应。当以藤黄微球菌为底物时，来自抗P环I.II抗血清的HEL - R - Abs也表现出对HEL酶活性的中和活性。
