Cosenza H, Quintáns J, Lefkovits I
Eur J Immunol. 1975 May;5(5):343-9. doi: 10.1002/eji.1830050510.
The anti-phosphorylcholine (PC) antibodies synthesized by BALB/c spleen cells in microcultures upon immunization with heat-killed vaccine of Pneumococci R36A (Pn) are directed exclusively to the PC epitope. These antibodies are of very restricted avidity and 88% of the responding clones express the idiotype characteristic of the TEPC-15 PC-binding myeloma. This idiotypic restriction appears to be due to the absence of clones capable of expressing other idiotypes, rather than to "clonal dominance". The estimated frequency of precursor cells for the PC epitope is 1 X 10(-5) to 2.5 X 10(-5). These precursors give rise to clones with an average size of 9 plaque-forming cells. When the logarithm of the number of negative wells was plotted against the number of spleen cells/well, the fraction of nonresponding cultures decreased exponentially as the number of spleen cells was increased. This indicated that only one cell type was limiting in our assay, presumably a B cell. Furthermore, treatment of spleen cells with AKR anti serum completely abolished the response to sheep red cells without affecting the response to PC. It is concluded that PC is a T cell-independent antigen. Of interest was the finding that PC requires adherent (A) cells and this is a particular characteristic of PC, since most T cell-independent antigens have been found not to require A cells. Reasons for the possible homogeneity of the response to PC are also discussed.
用肺炎球菌R36A（Pn）热灭活疫苗免疫后，BALB/c脾细胞在微量培养中合成的抗磷酸胆碱（PC）抗体仅针对PC表位。这些抗体的亲和力非常有限，88%的反应性克隆表达TEPC - 15 PC结合骨髓瘤的独特型特征。这种独特型限制似乎是由于缺乏能够表达其他独特型的克隆，而不是由于“克隆优势”。PC表位前体细胞的估计频率为1×10⁻⁵至2.5×10⁻⁵。这些前体细胞产生平均大小为9个空斑形成细胞的克隆。当将阴性孔数量的对数与每孔脾细胞数量作图时，随着脾细胞数量增加，无反应培养物的比例呈指数下降。这表明在我们的试验中只有一种细胞类型是限制因素，大概是B细胞。此外，用AKR抗血清处理脾细胞完全消除了对绵羊红细胞的反应，而不影响对PC的反应。得出的结论是PC是一种非T细胞依赖性抗原。有趣的是发现PC需要黏附（A）细胞，这是PC的一个特殊特征，因为大多数非T细胞依赖性抗原已被发现不需要A细胞。还讨论了对PC反应可能具有同质性的原因。
