Siekevitz M, Kocks C, Rajewsky K, Dildrop R
Cell. 1987 Mar 13;48(5):757-70. doi: 10.1016/0092-8674(87)90073-0.
Clonal progeny of naive B cells (producing a primary antibody response) and of memory B cells (producing a secondary response) were identified in a cell transfer system. Primary response clones are typically derived from IgM precursors and express unmutated V regions. Multiple isotype switches occur in these clones. Secondary response clones derive from IgG1 precursors and express highly mutated V regions. Additional switches do not occur. With one exception, there was no evidence for somatic mutation during clonal expansion. The generation of mutated memory cells may thus represent a distinct differentiation pathway. Evidence is presented that, in this pathway, mutants that have lost antigen binding specificity but that remain available for stimulation by a different antigen arise upon antigenic stimulation.
在细胞转移系统中鉴定出了初始B细胞（产生初次抗体应答）和记忆B细胞（产生二次应答）的克隆后代。初次应答克隆通常源自IgM前体细胞，表达未突变的V区。这些克隆中会发生多次同种型转换。二次应答克隆源自IgG1前体细胞，表达高度突变的V区。不会发生额外的转换。除了一个例外情况，在克隆扩增过程中没有体细胞突变的证据。因此，突变记忆细胞的产生可能代表了一条独特的分化途径。有证据表明，在这条途径中，在抗原刺激后会出现失去抗原结合特异性但仍可被不同抗原刺激的突变体。
