Cytokine and adhesion molecule expression in SCID mice reconstituted with CD4+ T cells

Area of Science:

• Immunology
• Gastroenterology

Background:

• Severe combined immunodeficient (SCID) mice are a model for studying immune reconstitution and inflammatory bowel disease.
• CD4+ T lymphocyte subsets play a critical role in immune responses and the development of colitis.

Purpose of the Study:

• To investigate the role of different CD4+ T lymphocyte subsets in inducing colitis in SCID mice.
• To quantify colonic cytokine and endothelial cell adhesion molecule (ECAM) expression in response to T cell transfer.

Main Methods:

• Reconstitution of SCID mice with CD45RBhigh or CD45RBlow CD4+ T lymphocytes.
• Assessment of clinical signs of colitis, including weight loss, stool consistency, and histopathology.
• Quantification of colonic cytokine and ECAM expression using molecular and immunohistochemical techniques.

Main Results:

• SCID mice reconstituted with CD45RBhigh T cells developed clinical and histopathological evidence of colitis.
• Colitic mice exhibited enhanced expression of Th1 and macrophage-derived cytokines (IFN-γ, TNF-α, IL-1β, IL-6, IL-12, IL-18, LTB).
• Significantly increased message levels and vascular surface expression of ICAM-1, VCAM-1, and MAdCAM-1 were observed in colitic mice, with some ECAMs elevated in distant tissues.

Conclusions:

• Reconstitution of SCID mice with CD45RBhigh T cells reliably induces chronic colitis.
• Colonic inflammation is associated with upregulated proinflammatory cytokines and ECAMs.
• CD45RBhigh T cell transfer enhances ECAM expression beyond the primary site of inflammation.