Fidler J M, Howard M, Schlegel R A, Vadas M, Shortman K
J Immunol. 1977 Mar;118(3):1076-82.
The characteristics of memory B cell antibody-forming cell (AFC) progenitors from long-term hapten-primed CBA mice were investigated by using sedimentation velocity and buoyant density separation to isolate physically distinct B cell sub-sets. The isolated fractions were assayed by the adoptive immune response to NIP-POL antigen, under conditions where neither T cells nor other accessory cells were limiting the IgM or IgG AFC responses. The results were compared to previous studies on the IgM AFC-progenitors of unprimed adult mice. Splenic IgM and IgG memory AFC-progenitor activity was largely found among the typical B cells of slow to medium sedimentation rate, in contrast to the fastre sedimenting IgM AFC-progenitor activity of unprimed animals. Splenic IgM and IgG memory AFC-progenitor activity was found among the medium to light density cells, and so resembled by this parameter the IgM AFC-progenitor activity in unprimed animals. Thoracic duct lymphocytes from hapten-primed mice also exhibited memory IgM and IgG AFC-progenitor activity in the slow-medium sedimentation range. However, in contrast to spleen, the IgM and IgG memory AFC-progenitor activity in lymph was found among very dense B cells. Two physically distinct sub-populations of memory B cells have thus been identified, namely: i) small, medium-light density, presumably tissue-resident B lymphocytes found in spleen; and ii) small, dense, presumably recirculating B lymphocytes found in lymph. Both physical forms include IgM and IgG progenitors. Both forms are distinct from the larger, medium-light density "virgin" AFC-progenitors in the spleen of unprimed adult mice.
通过使用沉降速度和浮力密度分离法来分离在物理性质上不同的B细胞亚群，研究了长期经半抗原致敏的CBA小鼠的记忆B细胞抗体形成细胞（AFC）祖细胞的特征。在T细胞和其他辅助细胞均不限制IgM或IgG AFC反应的条件下，通过对NIP-POL抗原的过继免疫反应来检测分离出的组分。将结果与先前关于未致敏成年小鼠的IgM AFC祖细胞的研究进行比较。与未致敏动物快速沉降的IgM AFC祖细胞活性相反，脾脏的IgM和IgG记忆AFC祖细胞活性主要存在于沉降速率慢至中等的典型B细胞中。脾脏的IgM和IgG记忆AFC祖细胞活性存在于中等密度至低密度的细胞中，因此在该参数上与未致敏动物的IgM AFC祖细胞活性相似。来自经半抗原致敏小鼠的胸导管淋巴细胞在沉降速率慢至中等的范围内也表现出记忆IgM和IgG AFC祖细胞活性。然而，与脾脏不同，在淋巴液中，IgM和IgG记忆AFC祖细胞活性存在于密度非常高的B细胞中。因此，已鉴定出两个在物理性质上不同的记忆B细胞亚群，即：i）在脾脏中发现的小的、中等密度至低密度的、可能是组织驻留的B淋巴细胞；ii）在淋巴液中发现的小的、高密度的、可能是再循环的B淋巴细胞。两种物理形式均包括IgM和IgG祖细胞。这两种形式均与未致敏成年小鼠脾脏中较大的、中等密度至低密度的“原始”AFC祖细胞不同。
