B cell-mediated regulatory mechanisms control tumor-promoting intestinal inflammation

Area of Science:

• Immunology
• Gastroenterology
• Oncology

Background:

• Mechanisms of inflammation in colitis-associated colorectal cancer (CAC) are not fully understood.
• B cells play critical roles in immune regulation, but their specific functions in CAC are unclear.

Purpose of the Study:

• To investigate distinct B cell-mediated immunoregulatory mechanisms in chronic colitis and CAC.
• To elucidate the roles of interleukin-10 (IL-10) and immunoglobulin A (IgA) plasma cells (PCs) in these processes.

Main Methods:

• Genetic studies to examine B cell functions.
• Analysis of B cell differentiation into IL-10-producing and IgA-producing plasma cells.
• Assessment of T helper cell responses and microbiota alterations in models of colitis and CAC.

Main Results:

• B cells inherently produce IL-10 and differentiate into IgA PCs upon Toll-like receptor (TLR) activation.
• B cell-derived IL-10 limits pathogenic T helper type 1 (Th1)/Th17 responses in chronic colitis.
• IgA PCs derived from IL-10+ B cells restrain tumorigenesis in CAC by promoting a tumor-protective intestinal environment and altering microbiota.

Conclusions:

• Regulatory B cell-mediated immunomodulation involves a temporal release of IL-10, followed by IgA production.
• Specific IgA-producing plasma cells influence the microbial community, controlling chronic inflammation and tumorigenesis in CAC.
• Distinct but interrelated B cell mechanisms regulate chronic colitis and CAC.