Oncostatin M transforms lymphoid tissue function in transgenic mice by stimulating lymph node T-cell development and...

Area of Science:

• Immunology
• Hematopoiesis
• Cytokine biology

Background:

• Oncostatin M (OM) is a cytokine in the IL-6 subfamily.
• OM is expressed in lymphoid tissues and activated leukocytes.
• Its role in lymphopoiesis and lymphoid tissue regulation requires further investigation.

Purpose of the Study:

• To investigate the effects of overexpressed Oncostatin M (OM) from different species on lymphopoiesis.
• To determine the mechanisms underlying OM-induced extrathymic T-cell development.
• To elucidate the impact of OM on thymus structure and function, and its potential to induce disease.

Main Methods:

• Generation of transgenic mice overexpressing human, bovine, or mouse OM genes.
• Lymphoid tissue analysis and cell accumulation studies.
• Reconstitution experiments with athymic mice.
• Breeding experiments with IL-6 and IL-7 receptor alpha-deficient mice.

Main Results:

• OM induced extrathymic T-cell development via an IL-7 receptor-dependent pathway, independent of IL-6.
• OM caused accumulation of immature B cells in the thymus and expansion of mature B and T cells.
• Transgenic thymus conversion to secondary lymphoid tissue resulted in a lethal autoimmune-like disease, characterized by autoantibodies, proteinuria, and glomerulonephritis.

Conclusions:

• Conserved phenotypes across species suggest OM's potent role in regulating lymphoid tissue function and morphogenesis.
• OM can induce T-cell development outside the thymus and B-cell accumulation within it.
• OM-induced lymphoid tissue alterations can lead to severe autoimmune pathology.