CD28 is a major T cell costimulatory molecule, delivering signals distinct from those of the CD3/TCR complex, which regulate cytokine and cytokine receptor expression, cell proliferation, and cell viability. CD28 needs to be cross-linked to initiate signals, yet both of its ligands, CD80 and CD86, are expressed as monomers. Previously, we determined the cytoplasmic tail of CD80 is required for ...

The interaction between CD28 on T cells and CD80 on APCs intensifies the linkage between TCR and MHC at the site of contact between T cells and APCs. In this study, we demonstrate that during human T cell/human APC interaction, the autologous or allogeneic human CD4(+) T cells become positive for the detection of CD80 at an early stage of activation (24 h). This detection of CD80 is attributabl...

The teleost non-specific cytotoxic cell (NCC), as the evolutionary precursors of NK cells, is an important population in innate immune system teleost. We have recently realized that costimulatory CD80/86 conservation structural and interactional features with its ligand CD28 Nile tilapia (Oreochromis niloticus). However, ability to regulate NCC activity has not been fully investigated. In prese...

CD80 plays a critical role in stimulation of T cells and subsequent control of infection. To investigate the effect of CD80 on HSV-1 infection, we constructed a recombinant HSV-1 virus that expresses two copies of the CD80 gene in place of the latency associated transcript (LAT). This mutant virus (HSV-CD80) expressed high levels of CD80 and had similar virus replication kinetics as control vir...

PURPOSE The CD80 (B7.1) molecule, which is a necessary costimulatory signal for T-cell activation and proliferation, is a powerful inducer of antitumor immunity. In this study, primary human ocular melanoma cells were transfected with a novel vector (B45-Neo episomal vector) containing the complementary DNA (cDNA) for human CD80 to determine if this vector system is useful for stimulating CD8+ ...

Activation of T cells usually requires two signals. Signal 1 is mediated via a peptide-MHC on the APC; signal 2 is mediated via a costimulatory molecule on the APC surface. We demonstrate here that naive CD4(+) T cells actually acquire the costimulatory molecule CD80 (B7-1) from syngeneic APCs after activation. This phenomenon was demonstrated showing acquisition of CD80 by T cells from CD80/CD...

T-cell tolerance is the central program that prevents harmful immune responses against self-antigens, in which inhibitory PD-1 signal given by B7-H1 interaction plays an important role. Recent studies demonstrated that B7-H1 binds CD80 besides PD-1, and B7-H1/CD80 interaction also delivers inhibitory signals in T cells. However, a role of B7-H1/CD80 signals in regulation of T-cell tolerance has...

CD80 expressed on the surface of APCs provides a positive costimulatory signal to naive CD4+ T cells via CD28 during activation. However, CD80 is also expressed on the surface of activated CD4+ T cells, and cross-linking CD80 on the surface of CD4+ T cells activated in the presence of Th1-promoting cytokines induces a direct up-regulation of T-bet, IFN-gamma, and Bcl(XL) expression in primary C...

The binding of costimulatory ligand CD80 to CD28 or CTLA-4 on T cells plays an important role in the regulation of the T cell response. We have examined the role of the cytoplasmic domain of CD80 in murine T cell costimulation and its organization in the immunological synapse (IS). Removal of CD80 cytoplasmic tail decreased its effectiveness in costimulating T cell proliferative response and ea...