CD8 T cells exhibit dynamic alterations in proliferation and apoptosis during various phases of the CD8 T-cell response, but the mechanisms that regulate cellular proliferation from the standpoint of CD8 T-cell memory are not well defined. The cyclin-dependent kinase inhibitor p27(Kip1) functions as a negative regulator of the cell cycle in T cells, and it has been implicated in regulating cell...

IL-7 is essential for the survival of naive and memory T cells, and IL-7 receptor alpha-chain (IL-7Ralpha) expression is dynamically regulated in activated CD8 T cells during acute viral and bacterial infections. Most virus-specific CD8 T cells become IL-7Ralpha(low) and are relatively short-lived, but some escape IL-7Ralpha repression (referred to as IL-7Ralpha(high) memory precursor effector ...

Recently, we identified two subsets of CCR7(-) memory CD8(+) T cells expressing high and low levels of the IL-7R alpha-chain (IL-7Ralpha) that is essential for memory T cell survival in human peripheral blood. IL-7Ralpha(low)CCR7(-) memory CD8(+) T cells that produce effector cytokines and perforin have impaired proliferation and survival in response to TCR triggering and IL-7, respectively. Th...

RATIONALE Proinflammatory adaptive immune responses are recognized as major drivers of atherosclerotic lesion formation. Although CD8(+) T cells have recently been proposed as a proatherogenic cell subset, their full scope of actions remains to be elucidated. OBJECTIVE We here addressed the contribution of CD8(+) T cells to monocyte trafficking in atherosclerosis. METHOD AND RESULTS We obse...

Viruses can cause a severe lymphopenia early in infection and a subsequent, lasting loss of pre-existing CD8(+) memory T cells. We therefore questioned how well virus Ag-specific memory CD8(+) T cells could reconstitute mice rendered lymphopenic as a consequence of genetics, irradiation, or viral or poly(I:C)-induced cytokines. In each case, reconstitution of the CD8(+) compartment was associat...

Although CD8(+) T cells initially suppress human immunodeficiency virus (HIV) replication, cytotoxic T-cell precursor frequencies eventually decline and fail to prevent disease progression. In a longitudinal study including 16 individuals infected with HIV-1, we studied both the number and function of HIV-specific CD8(+) T cells by comparing HLA-peptide tetramer staining and peptide-induced int...

BACKGROUND High expression of CD161 on CD8+ T cells is associated with a population of cells thought to play a role in mucosal immunity. We wished to investigate this subset in an HIV and Mycobacterium tuberculosis (MTB) endemic African setting. METHODS A flow cytometric approach was used to assess the frequency and phenotype of CD161++CD8+ T cells. 80 individuals were recruited for cross-sec...

Programmed Death 1 (PD-1) expression by human/simian immunodeficiency virus (HIV/SIV)-specific CD8 T cells has been associated with defective cytokine production and reduced in vitro proliferation capacity. However, the cellular mechanisms that sustain PD-1(high) virus-specific CD8 T cell responses during chronic infection are unknown. Here, we show that the PD-1(high) phenotype is associated w...

Proper T cell function relies on the integration of signals delivered by Ag, cytokine, and costimulatory receptors. In this study, the interactions between IL-2, CD27, and its ligand CD70 and their effects on human T cell function were examined. Unstimulated CD8(+) T cells expressed relatively low levels of CD70 and high levels of CD27. Incubation in vitro with high doses of IL-2 (3,000 IU/ml) ...

Lymphocyte Activation Gene-3 (LAG-3) is a transmembrane protein that binds MHC class II, enhances regulatory T cell activity, and negatively regulates cellular proliferation, activation, and homeostasis of T cells. Programmed Death 1 (PD-1) also negatively regulates T cell function. LAG-3 and PD-1 are both transiently expressed on CD8 T cells that have been stimulated during acute activation. H...