IL-10 producing T cells inhibit Ag-specific CD8+ T cell responses and may play a role in the immune dysregulation observed in HIV infection. We have previously observed the presence of HIV-specific IL-10-positive CD8+ T cells in advanced HIV disease. In this study, we examined the suppressive function of the Gag-specific IL-10-positive CD8+ T cells. Removal of these IL-10-positive CD8+ T cells ...

B6.K(b-)D(b-) mice are devoid of class Ia but express normal levels of class Ib molecules. They have low levels of CD8 T cells in both the thymus as well as peripheral T cell compartments. Although the percentage of splenic CD8 alpha alpha T cells is increased in these animals, approximately 90% of CD8 T cells are CD8 alpha beta. In contrast to B6 animals, most of the CD8 T cells from these mic...

After lymphocyte-depleted BMT, CD8+ T cells have been expanded to or above normal levels in 45% of the recipients within 3 months. The mechanisms underlying proliferation of donor-derived CD8+ T cells after BMT are still unclear. We investigated whether these CD8+ T cells proliferate in response to specific antigens by determination of TCR clonality and whether these cells exert specific cytoto...

Regulation of immune system is of paramount importance to prevent immune attacks against self-components. Mice deficient in the interleukin (IL)-2/IL-15 receptor beta chain, CD122, are model animals of such immune attacks and characteristically have a high number of abnormally activated T cells. Here, we show that the transfer of CD8+CD122+ cells into CD122-deficient neonates totally prevented ...

The activation of CD8+ suppressor T cells by normal intestinal epithelial cells in antigen-specific or allogeneic mixed cell culture systems has significant implications for the regulation of mucosal immune responses. In this study, we found that the capacity of epithelial cells to induce CD8+ suppressor T cell activation appeared to be linked to the binding of CD8 molecules on the T cell surfa...

An effective immune response requires the expansion and survival of a large number of activated T cells. This study compared the role of protein kinase C (PKC)theta and associated signaling molecules in the survival of activated primary CD4+ vs CD8+ murine T cells. We demonstrate that the absence of PKCtheta resulted in a moderate survival defect in CD4+ T cells and a striking survival defect o...

MHC class I-specific Ly49 inhibitory receptors regulate NK cell activation, thereby preventing autologous damage to normal cells. Ly49 receptors are also expressed on a subset of CD8+ T cells whose origin and function remain unknown. We report here that, despite their phenotypic and cytolytic similarities, Ly49+CD8+ T cells and conventional Ly49-CD44high memory-phenotype CD8+ T cells present st...

Sustained Ag persistence in chronic infection results in a deregulated CD8(+) T cell response that is characterized by T cell exhaustion and cell death of Ag-specific CD8(+) T cells. Yet, the underlying transcriptional mechanisms regulating CD8(+) T cell exhaustion and cell death are poorly defined. Using the experimental mouse model of lymphocytic choriomeningitis virus infection, we demonstra...

We have recently described an IL-2/IL-4-producing CD8+CD25+ non-regulatory memory T cell population that occurs in a subgroup of healthy elderly persons who characteristically still have a good humoral response after vaccination. The present study addresses this specific T cell subset and investigates its origin, clonal composition, Ag specificity, and replicative history. We demonstrate that C...