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Updated: Aug 9, 2026
Generation of Human CD40-activated B cells
Published on: October 17, 2009
Activation of human dendritic cells through CD40 cross-linking
C Caux1, C Massacrier, B Vanbervliet
1Schering-Plough, Laboratory for Immunological Research, Dardilly, France.
Insights
Dendritic Langerhans cells (D-Lc) express functional CD40, enhancing their survival and maturation. CD40 activation alters D-Lc phenotype, upregulating key molecules for T cell priming and immune responses.
Area of Science:
- Immunology
- Cell Biology
Background:
- Dendritic cells (DCs) are professional antigen-presenting cells crucial for T cell priming.
- CD40 is a molecule involved in B cell growth, differentiation, and monocyte activation.
- Dendritic Langerhans cells (D-Lc) are a type of DC with important immune functions.
Purpose of the Study:
- To investigate the expression and function of CD40 on D-Lc.
- To determine the effects of CD40 activation on D-Lc survival, morphology, phenotype, and cytokine secretion.
- To explore the potential physiological relevance of CD40-mediated D-Lc activation.
Main Methods:
- Generation of D-Lc from cord blood CD34+ progenitor cells using specific growth factors and cytokines.
- Culture of D-Lc on CD40-ligand (CD40L) transfected cells to activate CD40.
- Analysis of D-Lc survival, morphology, and phenotype using flow cytometry and microscopy.
- Measurement of cytokine secretion by activated D-Lc and monocytes.
Main Results:
- D-Lc express functional CD40 at a higher density than B cells.
- CD40 activation significantly enhances D-Lc survival and induces morphological changes, including increased dendrite development.
- CD40 triggering upregulates major histocompatibility complex class II, CD58, CD80, CD86, and CD25 on D-Lc, indicating maturation.
- CD40-activated D-Lc secrete TNF-alpha, IL-8, and MIP-1 alpha, while activated monocytes secrete a broader range of cytokines.
Conclusions:
- CD40 activation promotes D-Lc survival, maturation, and alters their phenotype, suggesting a role in immune regulation.
- The observed CD40-mediated effects on D-Lc may mimic physiological interactions with T cells.
- These findings highlight the importance of CD40 signaling in dendritic cell function and immune responses.
Abstract:
Dendritic cells, the professional antigen-presenting cells (APC) involved in T cell priming, express CD40, a molecule which triggering plays a key role in B cell growth and differentiation as well as monocyte activation. Herein we demonstrate that dendritic Langerhans cells (D-Lc) generated by culturing cord blood CD34+ progenitor cells with granulocyte/macrophage colony-stimulating and tumor necrosis factor alpha (TNF-alpha) express functional CD40 at a density higher than that found on B cells. Culturing D-Lc on CD40-ligand (CD40L) transfected L cells allowed D-Lc survival as 50 +/- 15% of seeded cells were recovered after 4 d while only 5% survived over control L cells. CD40 activation induced important morphological changes with a reduction of cytoplasmic content and a remarkable increase of dendrite development as well as an altered phenotype. In particular, CD40 triggering induced maintenance of high levels of major histocompatibility complex class II antigens and upregulation of accessory molecules such as CD58, CD80 (B7-1) and CD86 (B7-2). CD40 engagement also seems to turn on D-Lc maturation as illustrated by upregulation of CD25, a molecule usually expressed on interdigitating dendritic cells of secondary lymphoid organs. Finally, CD40 activated D-Lc secreted a limited set of cytokines (TNF-alpha, IL-8, and macrophage inflammatory protein 1 alpha [MIP-1 alpha]) whereas a similar activation induced elutriated monocytes to secrete IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, TNF-alpha, and MIP-1 alpha. As D-Lc activated T cells upregulated CD40L, it is likely that CD40 activation of D-Lc observed herein with a fibroblast cell line stably expressing CD40L, mimics physiological interactions between dendritic cells and T cells.
