Dendritic cells interact with CD4 T cells in intestinal mucosa

Area of Science:

• Immunology
• Gastrointestinal Biology
• Cellular Biology

Background:

• Nonmammalian species lack lymph nodes, and peripheral antigen-presenting cells (APCs) express MHCII.
• T cells can alter polarization post-lymph node presentation, suggesting extralymphoid roles for MHCII presentation.

Purpose of the Study:

• To investigate the role of MHCII-mediated antigen presentation by intestinal mucosal cells.
• To explore the in vitro and in vivo interactions between APCs and T cells in the gut.

Main Methods:

• In vitro antigen presentation assays using porcine intestinal MHCII(+) endothelial cells (ECs) and dendritic cells (DCs).
• In vivo colocalization studies of APCs and T cells in pig and mouse intestinal mucosa.
• Analysis of MHCII (DQ and DR) expression ratios on different mucosal APC subsets.

Main Results:

• Porcine intestinal ECs and DCs present antigen to T cells in vitro.
• APCs and T cells colocalize in the intestinal mucosa of pigs and mice.
• Endothelial involvement in APC-T cell interactions is age-dependent in pigs; DQ/DR ratios differ between ECs and other APCs.

Conclusions:

• Mucosal DCs can present antigens locally to primed T cells.
• Stromal APCs may be recruited for local antigen presentation in the gut.
• Local antigen presentation in the intestinal mucosa could influence effector T cell responses.