CD4+ T cells and Lactobacillus casei control relapsing colitis mediated by CD8+ T cells

Area of Science:

• Immunology
• Gastroenterology
• Microbiology

Background:

• CD4(+) regulatory T cells' role in controlling CD8(+) T cell-mediated colitis is not well-established.
• CD8(+) T cell-mediated colitis can be induced using hapten sensitization and challenge models.

Purpose of the Study:

• To investigate the capacity of CD4(+) T cells to control Ag-specific CD8(+) T cell-mediated colitis.
• To explore the therapeutic potential of probiotics in managing colitis.

Main Methods:

• Utilized a mouse model of CD8(+) T cell-mediated colitis induced by 2,4-dinitrobenzene sulfonic acid.
• Employed MHC class II-deficient mice and RAG2-deficient mice for cotransfer experiments.
• Assessed the impact of CD4(+) T cell depletion and Lactobacillus casei administration on colitis development and regulatory T cell function.

Main Results:

• CD4(+)CD25(+) T cells effectively prevented CD8(+) T cell-mediated colitis and suppressed CD8(+) T cell activation.
• Lack of CD4(+) regulatory T cells exacerbated both acute and relapsing colitis.
• Lactobacillus casei administration alleviated colitis and enhanced the suppressive function of Foxp3(+)CD4(+) regulatory T cells.

Conclusions:

• CD4(+) regulatory T cells are crucial for controlling colitogenic effector/memory CD8(+) T cells in acute and relapsing colitis.
• Probiotics, particularly Lactobacillus casei, show promise in alleviating colitis by modulating mucosal regulatory T cells.