Willers J, Weiler E, Kolb C
Department of Immunology, Faculty of Biology, University of Konstanz, Germany.
Scand J Immunol. 1995 Sep;42(3):345-52. doi: 10.1111/j.1365-3083.1995.tb03666.x.
The immune response of adult BALB/c mice against the bacterial antigen dextran B1355S (Dex) is well characterized as thymus independent (TI type 2) and Igha linked. The antisera consist of mainly IgM/lambda antibodies directed against the alpha(1-->3) glucosidic linkage. This study describes the immune response against the alpha(1-->3) linkage in the thymus dependent form (TD), i.e. tetra- or heptasaccharides (N4 or N7) of glucose as hapten coupled to chicken serum albumin (CSA) as carrier. Whereas athymic BALB/c-nu/nu mice did not respond to the TD antigens N4-CSA and N7-CSA, euthymic BALB/c showed high anti-Dex antibody titres of IgM and, after 2 degrees immunization, a class switch to IgG (mainly IgG1) isotypes with lambda light chains. The hapten N4 inhibited Dex-binding of M104E or of antisera from Dex or N4-CSA or N7-CSA immunized mice at 1.7-10 x 10(-4)M. The idiotype composition of these antibodies resembled those after Dex immunization. We conclude that the same Dex-specific precursor B cells have been stimulated by either form of antigen. The ontogenic development of a Dex-specific response could not be accelerated by the aid of T cells, even of adult origin. It seems, therefore, that the maturation of antigen specific B cells is the limiting step in ontogeny.
成年BALB/c小鼠针对细菌抗原右旋糖酐B1355S（Dex）的免疫反应已被充分表征为非胸腺依赖性（TI 2型）且与Igha连锁。抗血清主要由针对α(1→3)糖苷键的IgM/λ抗体组成。本研究描述了在胸腺依赖性形式（TD）下针对α(1→3)键的免疫反应，即葡萄糖的四糖或七糖（N4或N7）作为半抗原与鸡血清白蛋白（CSA）作为载体偶联。无胸腺的BALB/c-nu/nu小鼠对TD抗原N4-CSA和N7-CSA无反应，而有胸腺的BALB/c小鼠显示出高滴度的IgM抗Dex抗体，并且在二次免疫后，类别转换为带有λ轻链的IgG（主要是IgG1）同种型。半抗原N4在1.7 - 10×10⁻⁴M时抑制M104E或来自Dex、N4-CSA或N7-CSA免疫小鼠的抗血清与Dex的结合。这些抗体的独特型组成类似于Dex免疫后的情况。我们得出结论，两种形式的抗原均刺激了相同的Dex特异性前体B细胞。即使借助成年来源的T细胞，Dex特异性反应的个体发生发育也无法加速。因此，似乎抗原特异性B细胞的成熟是个体发生中的限制步骤。
