CD19 regulates innate immunity by the toll-like receptor RP105 signaling in B lymphocytes.

Published

Journal Article

Lipopolysaccharide (LPS) is a major gram-negative bacterial component that stimulates innate immune response and also induces B-lymphocyte activation. Recent studies have revealed that common molecular patterns of microorganisms such as LPS are recognized by toll-like receptors (TLRs). B cells have 2 known TLRs that mediate LPS signaling, TLR4 and RP105 (CD180). While TLR4 is expressed on immune cells of various types, RP105 is preferentially expressed on mature B cells. Here we demonstrate that CD19 plays a major role in regulating signal transduction through RP105. Anti-RP105 ligation induced normal proliferation of B cells from mice deficient for MyD88, an adaptor protein that mediates most TLR pathways. By contrast, the loss of CD19 resulted in modest B-cell proliferation against anti-RP105 stimulation as well as LPS stimulation. LPS induced tyrosine phosphorylation of CD19, which was RP105-dependent but TLR4-independent. CD19 formed a complex with Lyn and Vav following RP105 ligation, and CD19 expression was required for optimal Lyn activation and Vav phosphorylation. Consistently, B cells deficient for CD19 exhibited specific defect in the activation of c-Jun N-terminal kinases following RP105 ligation and LPS stimulation. In contrast, CD19 and phosphatidylinositol 3-kinase independently regulated intracellular calcium mobilization induced by anti-RP105 stimulation. Thus, signaling through the B-cell-specific LPS receptor RP105 is uniquely regulated by the B-cell-specific signaling component, Lyn/CD19/Vav complex.

Full Text

Duke Authors

Cited Authors

  • Yazawa, N; Fujimoto, M; Sato, S; Miyake, K; Asano, N; Nagai, Y; Takeuchi, O; Takeda, K; Okochi, H; Akira, S; Tedder, TF; Tamaki, K

Published Date

  • August 15, 2003

Published In

Volume / Issue

  • 102 / 4

Start / End Page

  • 1374 - 1380

PubMed ID

  • 12714520

Pubmed Central ID

  • 12714520

International Standard Serial Number (ISSN)

  • 0006-4971

Digital Object Identifier (DOI)

  • 10.1182/blood-2002-11-3573

Language

  • eng

Conference Location

  • United States