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Updated: Aug 8, 2026
Murine Model of CD40-activation of B cells
Published on: March 6, 2010
Impaired T cell-mediated macrophage activation in CD40 ligand-deficient mice
1Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614-0579, USA.
Insights
CD40 ligand (CD40L) is crucial for T cell-dependent immune responses. Mice lacking CD40L show impaired T cell activation of macrophages, highlighting CD40L
Area of Science:
- Immunology
- Cellular Biology
- Molecular Medicine
Background:
- CD40 ligand (CD40L) is essential for T cell-dependent antibody (Ab) responses.
- The role of CD40L in cell-mediated immunity, particularly macrophage activation, requires further investigation.
Purpose of the Study:
- To assess the critical role of CD40L in T cell-mediated activation of macrophage effector functions.
- To determine the impact of CD40L deficiency on immune responses involving T cells and macrophages.
Main Methods:
- Utilized CD40L knockout (KO) mice and wild-type (+/+) littermates.
- Assessed the ability of CD4+ T cells to activate allogeneic macrophages in vitro.
- Measured nitric oxide (NO) production, inflammatory cytokine (TNF-alpha) release, and reactive nitrogen intermediate (RNI) generation by macrophages.
Main Results:
- CD4+ T cells from CD40L-KO mice were fourfold less effective in activating nitric oxide responses in macrophages compared to +/+ T cells.
- Fixed CD40L-KO T cells failed to induce TNF-alpha or RNI generation in macrophages after 6 hours.
- Both CD40L-KO and +/+ T cells induced weak macrophage responses after 24 hours of activation.
Conclusions:
- CD40L expression is critical for efficient T cell-mediated activation of macrophage effector functions.
- Deficiency in CD40L leads to impaired T cell-dependent macrophage-mediated immune responses.
- CD40L plays a dominant role in early T cell-macrophage interactions crucial for immune activation.
Abstract:
The expression of the ligand for CD40 (CD40L) is critical for induction of T cell-dependent Ab responses. To examine how critical the expression of CD40L is for induction of cell-mediated immune responses, the ability of T cells from CD40L knockout mice to activate macrophage effector function was assessed. CD4+ T cells from CD40L-knockout mice were fourfold less effective than +/+ T cells in activating the nitric oxide response in allogeneic macrophages. CD40L-knockout T cells that were fixed with paraformaldehyde after a 6-h activation period, a time point at which CD40L dominates the macrophage-activating capability of the T cell, could activate neither macrophage production of inflammatory cytokines (TNF-alpha) nor generation of reactive nitrogen intermediates. After 24 h of activation, however, both CD40L-knockout and +/+ T cells could induce similar but weak responses from the macrophages. This study demonstrates that animals deficient in CD40L expression display a deficiency in T cell-dependent macrophage-mediated immune responses.
