The functional link between the immune suppression gene and Mhc class II molecules

Area of Science:

• Immunology
• Genetics

Background:

• The immune response to bovine insulin (BI) in rats is regulated by major histocompatibility complex (MHC)-linked immune response (Ir-BI) and immune suppression (Is-BI) genes.
• Investigating low responsiveness to BI in WKAH rats (RT1k) is crucial for understanding immune regulation.

Purpose of the Study:

• To explore the functional link between the immune suppression gene (Is-BI) and MHC class II molecules.
• To elucidate the mechanisms underlying low responsiveness to bovine insulin in WKAH rats.

Main Methods:

• Analysis of lymph node cells (LNC) from low responder WKAH rats.
• In vitro culture with varying antigen concentrations and elimination of specific T cell populations (OX8+).
• Assessment of T cell proliferation and suppression assays using BI, BI-B chain, and pork insulin.

Main Results:

• WKAH rat LNC responded to BI after OX8+ T cell elimination or with high antigen doses.
• RT1.Dk-restricted proliferative responses to BI were observed after OX8+ T cell removal.
• OX8+ T cells suppressed anti-BI responses, indicating their role as suppressor T (Ts) cells.
• Suppressive activity of OX8+ Ts cells was diminished by eliminating antigen-presenting cells (APC) or using RT1.Bk-specific monoclonal antibodies.

Conclusions:

• Proliferating T cell repertoires recognizing BI-B chain in the context of RT1.Dk molecules exist in WKAH rats.
• Low responsiveness to BI is largely mediated by antigen-specific OX8+ suppressor T cells.
• Recognition of BI with RT1.Bk molecules on APC is necessary for the induction phase of OX8+ Ts cells.