Kihira T, Kawanishi H
UMDNJ-Robert Wood Johnson Medical School, New Brunswick 08903, USA.
Immunol Invest. 1995 Aug;24(5):701-11. doi: 10.3109/08820139509060699.
The objective of this study was to demonstrate in vitro that bone marrow-derived pro/pre-B cells bearing mu mRNA can switch their Ig heavy-chain isotype to that of alpha mRNA-expressing B cells after contact with Peyer's patches-derived activated autoreactive CD4+ T cells. Bone marrow-derived pro/pre-B cells and activated autoreactive Peyer's patch, mesenteric lymph node, or spleen CD4+ T cells were co-cultured in the presence of recombinant (r) IL-2, rIL-7, and Con A for 3 days. The mixed cultured cells were isolated for preparation of total RNA. Dot/slot hybridization, using murine C mu (pu3741) and C alpha (P alpha J558) Ig heavy-chain cDNA probes, detected C mu and C alpha Ig heavy-chain mRNA transcripts. The magnitude of each mRNA expression was measured demsitometrically. In addition, the secreted class-specific Ig contents from the co-cultured supernatants were measured. The results indicate that activated autoreactive Peyer's patch and mesenteric lymph node CD4+ T cells provide a specific Ig heavy-chain switch from mu to alpha (Peyer's patch CD4+ T cells > mesenteric lymph node CD4+ T cells) in bone marrow-derived pro/pre-B cells and also assist to develop IgA-secreting plasma cells. The alpha heavy-chain switch and IgA production do not occur in the presence of activated autoreactive spleen CD4+ T cells. These results support the view that autoreactive gut Peyer's patch CD4+ T cells, at least, regulate IgA B cell heavy-chain switching and terminal differentiation during gut mucosal B cell development.
本研究的目的是在体外证明，携带μ mRNA的骨髓源前B细胞/前B细胞在与派尔集合淋巴结来源的活化自身反应性CD4⁺ T细胞接触后，可将其免疫球蛋白重链同种型转换为表达α mRNA的B细胞的同种型。将骨髓源前B细胞/前B细胞与活化的自身反应性派尔集合淋巴结、肠系膜淋巴结或脾脏CD4⁺ T细胞在重组（r）IL-2、rIL-7和刀豆蛋白A存在的情况下共培养3天。分离混合培养的细胞以制备总RNA。使用小鼠Cμ（pu3741）和Cα（PαJ558）免疫球蛋白重链cDNA探针进行点/狭缝杂交，检测Cμ和Cα免疫球蛋白重链mRNA转录本。通过光密度测定法测量每种mRNA表达的强度。此外，还测量了共培养上清液中分泌的类别特异性免疫球蛋白含量。结果表明，活化的自身反应性派尔集合淋巴结和肠系膜淋巴结CD4⁺ T细胞可使骨髓源前B细胞/前B细胞的免疫球蛋白重链从μ特异性转换为α（派尔集合淋巴结CD4⁺ T细胞＞肠系膜淋巴结CD4⁺ T细胞），并有助于产生分泌IgA的浆细胞。在活化的自身反应性脾脏CD4⁺ T细胞存在的情况下，不会发生α重链转换和IgA产生。这些结果支持这样一种观点，即至少自身反应性肠道派尔集合淋巴结CD4⁺ T细胞在肠道黏膜B细胞发育过程中调节IgA B细胞重链转换和终末分化。
