Immunology and Radiotherapy

Immune Response Regulation

The interaction of cell surface receptors with secreted cytokines and with one another tightly controls the immune response, and several groups are investigating the mechanisms by which these interactions have regulatory effects. Understanding how specialised cells or anatomical regions, such as vascular endothelial cells or the epidermis, control and guide the immune response is another important area of research.

The pathogenesis of IBD depends on the interaction of effector T cells and APCs. APCs ingest the antigens that support the inflammatory response. Epitope is presented in the context of MHC class II as a result of antigen degradation within proteasomes. The CD4+ T cell and macrophage engage specifically with antigens when MHC classes II and the T-cell receptor (CD3) connect. The T cell must occur, but it is not enough to activate it. Because binding of CD3 to MHC class II without a co-stimulatory signal might result in energy or apoptosis, a second co-stimulatory signal is also required. Co-stimulatory signals of importance include TNF-TNF receptor, CD40-CD40 ligand, and B7-CD28 binding.