Lutzker S, Rothman P, Pollock R, Coffman R, Alt F W
Howard Hughes Medical Institute, Columbia University, New York, New York 10032.
Cell. 1988 Apr 22;53(2):177-84. doi: 10.1016/0092-8674(88)90379-0.
Treatment of murine B cells with bacterial lipopolysaccharide (LPS) in the presence or absence of different lymphokines results in cell populations that differentially express particular immunoglobulin heavy chain constant region (CH) genes. This class switch involves recombination between switch regions located upstream of the germ-line CH genes. We have treated Abelson murine leukemia virus-transformed pre-B cells and normal splenic B cells with LPS or LPS plus the lymphokine IL-4 and examined the effect on the germ-line gamma 2b locus and gamma 2b class switching. In both cell types, LPS induces transcription specifically through the germ-line gamma 2b locus before gamma 2b class switching. Furthermore, IL-4 inhibits LPS induction of germ-line gamma 2b transcripts in spleen cells and correspondingly abrogates switching to this CH gene. Thus treatment with mitogens and lymphokines can alter transcription of germ-line CH genes in B lineage cells and thereby directly regulate class switching in the context of a recombinase accessibility mechanism.
在存在或不存在不同淋巴因子的情况下，用细菌脂多糖（LPS）处理小鼠B细胞，会产生差异表达特定免疫球蛋白重链恒定区（CH）基因的细胞群体。这种类别转换涉及位于种系CH基因上游的转换区之间的重组。我们用LPS或LPS加淋巴因子IL-4处理了艾贝尔逊鼠白血病病毒转化的前B细胞和正常脾B细胞，并研究了对种系γ2b基因座和γ2b类别转换的影响。在两种细胞类型中，LPS在γ2b类别转换之前特异性地通过种系γ2b基因座诱导转录。此外，IL-4抑制脾细胞中种系γ2b转录本的LPS诱导，并相应地消除向该CH基因的转换。因此，用丝裂原和淋巴因子处理可以改变B系细胞中种系CH基因的转录，从而在重组酶可及性机制的背景下直接调节类别转换。
