Essential to the functionality of a BCR is the presence of CD19. [20] Experiments using CD19 knockout mice found that CD19 is essential for B cell differentiative events including the formation of B-1, germinal center, and marginal zone (MZ) B cells.

CD19 is a biomarker for normal and neoplastic B cells, as well as follicular dendritic cells. CD19 is critically involved in establishing intrinsic B cell signaling thresholds through modulating both B cell receptor-dependent and independent signaling.

In response to membrane-bound ligand stimulation, antigen aggregation occurs in B cell antigen receptor (BCR) microclusters containing immunoglobulin (Ig) M and IgD that recruit the kinase Syk and transiently associate with the coreceptor CD19.

Dec 2, 2007 · CD19 is a B cell–specific coreceptor expressed at early stages of B cell development. It has been shown to enhance signaling through the BCR. In the plasma membrane of B cells, CD19 is...

CD19 is a co-stimulatory surface protein expressed exclusively on B cells and serves to reduce the threshold for signalling via the B-cell receptor (BCR). Co-ligation of CD19 with the BCR synergistically enhances mitogen-activated protein (MAP) kinase activity, calcium release and …

Jan 15, 2021 · Signaling through the CD19-CD81 co-receptor complex, in combination with the B cell receptor, is a critical determinant of B cell development and activation. It is unknown how CD81 engages CD19 to enable co-receptor function.

Jun 25, 2024 · CD19 is the essential signaling subunit of a multi-component co-receptor complex that functions in concert with the BCR to execute the cellular response to antigen.

B cell activation is regulated by a variety of signals. CD19 positively regulates B cell activation, augmenting signals delivered through the BCR complex. In contrast, CD32b contains an ITIM and negatively regulates BCR signaling.

Jul 1, 2001 · Current evidence indicates that CD19 acts as a specialized membrane adaptor protein for the BCR that amplifies the activity of the Src family kinase Lyn, and recruits Vav, resulting in the activation of mitogen-activated protein …

Here in this review, we summarize the latest development on the major functions of CD19 as both positive and negative regulator of BCR signaling in different situations and highlight the correlation and mechanisms of disturbed CD19 expression with autoimmune diseases and B cell lymphomas.