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Updated: Aug 8, 2026
Generation of Human CD40-activated B cells
Published on: October 17, 2009
CD40, but not CD154, expression on B cells is necessary for optimal primary B cell responses
Byung O Lee1, Juan Moyron-Quiroz, Javier Rangel-Moreno
1Trudeau Institute, Saranac Lake, NY 12983, USA.
Insights
CD40 on B cells is crucial for germinal center formation, isotype switching, and antibody production. However, CD154 expression on B cells is not required for these essential B cell responses in vivo.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD40 and its ligand CD154 are key costimulatory molecules involved in immune responses.
- Previous studies showed CD40 or CD154 deficiency impairs B cell functions like isotype switching and antibody production.
Purpose of the Study:
- To determine if CD40 or CD154 expression on B cells is intrinsically required for optimal B cell responses in vivo.
- To elucidate the primary pathway for B cell activation and differentiation.
Main Methods:
- Utilized bone marrow chimeric mice to investigate the roles of CD40 and CD154 expression on specific cell types.
- Assessed B cell responses including germinal center formation, isotype switching, and antibody production.
Main Results:
- CD40 expression on B cells is essential for germinal center formation, isotype switching, and sustained antibody production, even when other antigen-presenting cells express CD40.
- CD154 expression on B cells is not required for these B cell functions; normal responses were observed when CD154 was limited to T cells.
Conclusions:
- The interaction between CD154 on T cells and CD40 on B cells is the primary pathway for B cell activation and differentiation.
- CD154 expression on B cells does not significantly contribute to B cell activation and differentiation in vivo.
Abstract:
CD40 is an important costimulatory molecule for B cells as well as dendritic cells, monocytes, and other APCs. The ligand for CD40, CD154, is expressed on activated T cells, NK cells, mast cells, basophils, and even activated B cells. Although both CD40(-/-) and CD154(-/-) mice have impaired ability to isotype switch, form germinal centers, make memory B cells, and produce Ab, it is not entirely clear whether these defects are intrinsic to B cells, to other APCs, or to T cells. Using bone marrow chimeric mice, we investigated whether CD40 or CD154 must be expressed on B cells for optimal B cell responses in vivo. We demonstrate that CD40 expression on B cells is required for the generation of germinal centers, isotype switching, and sustained Ab production, even when other APCs express CD40. In contrast, the expression of CD154 on B cells is not required for the generation of germinal centers, isotype switching, or sustained Ab production. In fact, B cell responses are completely normal when CD154 expression is limited exclusively to Ag-specific T cells. These results suggest that the interaction of CD154 expressed by activated CD4 T cells with CD40 expressed by B cells is the primary pathway necessary to achieve B cell activation and differentiation and that CD154 expression on B cells does not noticeably facilitate B cell activation and differentiation.
