Weak agonist self-peptides promote selection and tuning of virus-specific T cells.

Recent progress has begun to define the interactions and signaling pathways that are triggered during positive selection. To identify and further examine self-peptides that can mediate positive selection, we searched a protein-database to find peptides that have minimal homology with the viral peptide (p33) that activates a defined P14 transgenic TCR. We identified four peptides that could bind the restriction element H-2D(b) and induce proliferation of P14 transgenic splenocytes at high concentration.

Enhanced T cell responses contribute to the genetic predisposition of CD8-mediated spontaneous autoimmunity.

A number of factors have been demonstrated to influence the induction of pathogenic autoimmune responses, including the loss of regulatory T cells. To assess the contribution of regulatory T cells in CD8(+) T cell-mediated autoimmunity, RIP-gp/P14 double-transgenic mice expressing the lymphocytic choriomeningitis virus (LCMV) glycoprotein (gp) on pancreatic beta-islet cells, together with T cells expressing an LCMV-gp-specific T cell receptor (TCR), were crossed to RAG 2-deficient mice. The loss of potentially regulatory T cells, however, did not contribute to diabetes induction.