English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In this study we determined the role of immunoglobulin (Ig) germline transcripts in the isotype switch differentiation of the cloned lymphoma B cell line CH12.LX. In initial studies, we showed that addition of transforming growth factor beta (TGF-beta) and interleukin 4 (IL-4), either alone or in combination, augment switching from membrane (m)IgM+ to mIgA+ cells, and that increased switching is preceded and paralleled by an increase in the steady-state level of alpha germline transcripts (alpha GLT). Interestingly, TGF-beta and IL-4 affect switching in different ways, as shown by the fact that IL-4 increases and TGF-beta decreases the number of dual-positive (mIgM+/mIgA+) cells; in addition, TGF-beta and IL-4 have different effects on the time course of induction of alpha GLT. In subsequent studies, we established that we could downregulate alpha GLT levels in CH12.LX B cells by transfecting an expression vector that can be induced to produce transcripts antisense to the I alpha exon. Using this approach we downregulated alpha GLT in CH12.LX B cells undergoing switching in the presence of TGF-beta and IL-4 and showed that such downregulation led to decreased switching, as evidenced by decreased appearance of dual-positive B cells as well as decreased IgA synthesis relative to IgM synthesis. This result was corroborated by the fact that incubation of CH12.LX cells with phosphorothio-oligo antisense DNA to I alpha sequence also led to a decrease in the number of dual-positive cells and in the IgA/IgM secretion ratio. In summary, IgA isotype differentiation in CH12.LX B cell, particularly the steps necessary for the elaboration of mIgM+/mIgA+ switch intermediate cells, is inhibited by downregulation of alpha GLT; it is therefore apparent that alpha GLT plays a key role in the initial stage of isotype switch differentiation.

Effect of downregulation of germline transcripts on immunoglobulin A isotype differentiation.