objectives: platelets are anucleated fragments derived from megakaryocytes. it has been demonstrated that platelets play a role in hemostasis and innate immunity. in addition, platelets have a cd40 ligand which is an important molecular marker in motivating immune cells. thus, platelets also have a role in adaptive immunity as seen by their ability to activate b cells. since human platelet micr...

CD80 and CD86 expressed on the surface of antigen-presenting cells interact with cytotoxic T lymphocyte antigen-4 [CTLA-4 (CD152)] expressed on activated T cells and mediate critical T cell inhibitory signals. CD80 and CD86 are type I glycoproteins, and are made up of two extracellular (EC) Ig-like domains-a transmembrane region and a cytoplasmic tail. The N-terminal (V domain) and membrane-pro...

AIM The lack of potent innate immune responses during HCV infection might lead to a delay in initiating adaptive immune responses. Kupffer cells (KCs) and liver-infiltrating monocytes/macrophages (CD68+ cells) are essential to establish effective anti-HCV responses. They express co-stimulatory molecules, CD80 and CD86. CD86 upregulation induces activator responses that are then potentially regu...

Cytotoxic T-lymphocyte antigen 4 (CTLA4) is a well-studied T cell costimulatory receptor that is known to inhibit T cell activation. In this study, the relationship between strength of the first signal and costimulatory interactions on primary mouse CD4(+) T cells was investigated. CTLA4-CD80/CD86 interactions differentially modulate T cell cycling based on the mode of CD3 signal: Activation wi...

Deficiencies in B7:CD28 costimulation are considered to be one of the major causes of the failure to generate a tumor-specific immune response. Up-regulating the expression of the B7 molecules on malignant B cells has been shown to stimulate cytotoxic T cells. Plasma cells from patients with myeloma express a tumor-specific idiotype but lack CD80 (B7-1) and have a variable expression of CD86 (B...

CD86 molecule is the ligand for both costimulatory (CD28) and coinhibitory (CTLA-4) molecules, and it regulates immune response after allogeneic hematopoietic stem cell transplantation (alloHSCT). Therefore, we postulate that CD86 gene variations might influence the outcome after alloHSCT. Altogether, 295 adult patients (pts) undergoing related (105 pts) and unrelated (190 pts) donor-matched HS...

Efficient T-cell activation requires two signals. The first signal, which confers specificity, is provided by interaction of the T-cell receptor with peptides presented by MHC molecules. One of the second costimulatory signals is induced by binding of B7 proteins on the surface of antigen-presenting cells to CD28 on the T-cell surface. Expression of B7 molecules on tumor cells can result in the...

The cytokine IL-21 is a potent immune modulator with diverse mechanisms of action on multiple cell types. IL-21 is in clinical use to promote tumor rejection and is an emerging target for neutralization in the setting of autoimmunity. Despite its clinical potential, the biological actions of IL-21 are not yet fully understood and the full range of effects of this pleiotropic cytokine are still ...

In this study, we investigated the role of a transcription factor, PU.1, in the regulation of CD80 and CD86 expression in dendritic cells (DCs). A chromatin immunoprecipitation assay revealed that PU.1 is constitutively bound to the CD80 and CD86 promoters in bone marrow-derived DCs. In addition, co-expression of PU.1 resulted in the transactivation of the CD80 and CD86 promoters in a reporter ...