Interactions between macrophages and lymphocytes through costimulatory molecules and cytokines are essential for mounting an efficient immune response and controlling its pathogenic potential. Here we demonstrate the immunomodulatory capacity of Trypanosoma cruzi, the causative agent of Chagas' disease, through its ability to induce differential expression of costimulatory molecules and cytokin...

PURPOSE T lymphocytes have a central role in allograft rejection. On engagement of the T cell receptor by antigenic peptide-major histocompatibility complex (MHC) complex, a second "costimulatory" signal is critical to full T-cell activation or downregulation. In this study, the effect on corneal allograft survival of modulation of the costimulatory molecules programmed death-1 (PD-1) and induc...

Adoptive transfer of T cells genetically modified to express cancer-specific receptors can mediate impressive tumor regression in terminally ill patients. However, T cell function and persistence over time could be hampered by the activation of inhibitory costimulatory pathways, such as programmed death 1 (PD1)/programmed death ligand 1, leading to T cell exhaustion and providing tumor cells wi...

BACKGROUND T cells and B cells communicate by direct cell--cell interaction that is crucial to the functioning of the immune system. It is well established that the interaction between B-cell-expressed CD40 and T-cell-expressed CD40 ligand (CD40L) is critical for T-cell-dependent antibody responses, but the role of this interaction in T-cell responses is less clear. In this study, we have used ...

Evidence from many human and rodent studies has established that T lymphocytes enhance inflammation in atherosclerotic plaques and contribute to lesion progression and remodeling. Recent work also indicates that regulatory T cells are important in limiting proatherogenic T-cell responses. Given the important role of T cells in atherosclerosis, there is a need to fully understand how proatheroge...

It is well established that T lymphocytes undergo homeostatic proliferation in lymphopenic environment. The homeostatic proliferation requires recognition of the major histocompatibility complex on the host. Recent studies have demonstrated that costimulation-mediated CD28, 4-1BB, and CD40 is not required for T cell homeostatic proliferation. It has been suggested that homeostatic proliferation...

CD1d-restricted Valpha14(+) invariant NK T (iNKT) cells are a specialized alphabeta T cell subset that regulates both innate and adaptive immunity. Although costimulatory molecules are required for the activation of conventional T cells and for the development of Foxp3(+) T cells, their role in iNKT cell regulation is unclear. Here we report that mice deficient in CD80/CD86 and/or B7h exhibit s...