Jones J M, Amsbaugh D F, Prescott B
J Immunol. 1976 Jan;116(1):52-64.
When the number of PFC present in the spleen was measured at 24-hr intervals after immunizing with an optimally immunogenic dose of type III pneumococcal polysaccharide (SSS-III), maximal numbers of PFC were attained 4 days after immunization; thereafter, the number of PFC decreased rapidly. By contrast, serum antibody levels, which were measured in the same mice using a Farr test, reached peak values 5 days after immunization and then declined much more slowly than did the number of PFC. Two factors were found to contribute to this disparity. First, experiments conducted with splenectomized mice showed that extrasplenic antibody synthesis, which began between days 3 and 4 after immunization and peaked on days 6 to 7, accounted for nearly one-third of the total amount of serum antibody produced. Second, the average rate of antibody synthesis by PFC increased through day 6 after immunization and then declined. Antigen-antibody dissociation tests showed that the avidity of the serum antibody obtained 4 to 7 days after immunization was the same. Moreover, during the same interval, all the antibody detected by the Farr test was of the IgM class. Thus, a change in avidity or class of immunoglobulin after day 5 did not account for the disparity observed. The clearance rate of antibody injected i.v. into nonimmune and immunized mice was studied. The data obtained indicated that accelerated clearance of antibody was occurring prior to day 3 after immunization; however, after day 3 the antibody clearance rate was constant and was the same as that found when antibody was injected into nonimmune mice. These findings affirmed the results of previous studies showing that treadmill neutralization was not important in determining the serum antibody levels present after immunization with an optimally immunogenic dose of SSS-III.
在用最佳免疫原性剂量的Ⅲ型肺炎球菌多糖（SSS-III）免疫后，每隔24小时测量脾脏中存在的PFC数量，免疫后4天达到PFC的最大数量；此后，PFC数量迅速下降。相比之下，使用Farr试验在同一只小鼠中测量的血清抗体水平在免疫后5天达到峰值，然后下降速度比PFC数量慢得多。发现有两个因素导致了这种差异。首先，对脾切除小鼠进行的实验表明，脾外抗体合成在免疫后第3至4天开始，并在第6至7天达到峰值，占血清抗体产生总量的近三分之一。其次，PFC的平均抗体合成速率在免疫后第6天之前增加，然后下降。抗原-抗体解离试验表明，免疫后4至7天获得的血清抗体的亲和力相同。此外，在同一时间段内，Farr试验检测到的所有抗体均为IgM类。因此，第5天后免疫球蛋白亲和力或类别的变化并不能解释所观察到的差异。研究了静脉注射抗体到未免疫和免疫小鼠中的清除率。获得的数据表明，免疫后第3天之前抗体清除加速；然而，第3天后抗体清除率恒定，与将抗体注射到未免疫小鼠中时的清除率相同。这些发现证实了先前研究的结果，即跑步机中和在确定用最佳免疫原性剂量的SSS-III免疫后存在的血清抗体水平方面并不重要。
