"B7-transfected CHO cells can induce suboptimally activated CD28+ T cells to proliferate and secrete high levels of interleukin 2"

"mAb 9.3 was capable of inducing T cell proliferation in the presence of 12-o-tetradecanoyl phorbol-13-acetate (TPA)"

"triggering of T lymphocytes with 9.3 antibody (in the presence of adherent cells) resulted in strong IL-2 production that peaked at 48 h"

"Two hydrophobic residues in the V-like domain of CD80 were identified as critical for binding to CD28 and are also important for the interaction with CTLA4"

"One of these residues, Y87, is conserved in all CD80 and CD86 cloned from various species"

"p56Lck and p59Fyn phosphorylate CD28 primarily at Tyr-191 of the Tyr-Met-Asn-Met motif, inducing a 3- to 8-fold increase in p85 (subunit of PI 3-kinase) and GRB-2 SH2 binding to CD28"

"CD28 interacts with three intracellular proteins-phosphatidylinositol 3-kinase (PI 3-kinase), T cell-specific protein-tyrosine kinase ITK (formerly TSK or EMT), and the complex between growth factor receptor-bound protein 2 and son of sevenless guanine nucleotide exchange protein (GRB-2-SOS)"

"Y191 mutation (Y191CD28F) disrupted both PI 3-kinase and GRB-2 binding"

"M194 mutation (M194CD28C) disrupted only PI 3-kinase binding"

"Both Y191CD28F and M194CD28C mutants failed to generate IL-2. These data directly implicate PI 3-kinase in CD28-mediated costimulation leading to IL-2 secretion"

"CTLA-4 can also associate with PI 3-kinase as detected by lipid kinase analysis and immunoblotting with anti-p85 antiserum"

"the NH2- and COOH-terminal SH2 domains of p85 bind the CTLA-4 cytoplasmic pYVKM motif with an affinity (ID50: 0.6 and 0.04 microM), that is similar to CD28"

"IL-4 synthesis was greatly enhanced by triggering of CD40L on the T cell surface in conjunction with ligation of CD3/TCR and CD28"

"ligation of CD3/TCR and CD28 in the absence of CD40L triggering resulted in little or no IL-4 synthesis"

"The CD28/B7 receptor/ligand system is one of the dominant costimulatory pathways. Interruption of this signaling pathway with CD28 antagonists not only results in the suppression of the immune response, but in some cases induces antigen-specific tolerance"

"the Grb2 SH2 domain is critical for the association, while the SH3 domain plays an additional role in facilitating optimal binding"

"Mutations that alter Grb2 binding were found to block the CD28-dependent interleukin-2 production. Further, tyrosine phosphorylation of Vav and the costimulation-dependent activation of Jun N-terminal kinase was blocked"

"the costimulation-dependent activation of Jun N-terminal kinase was blocked in cells defective in CD28/Grb2 binding"

"The current model of T cell activation requires two signals. The first signal is specific, requiring T cell receptor recognition and binding to MHC/Antigen presented by an antigen-presenting cell. The second signal is nonspecific, resulting from the binding of B7 ligand on the antigen-presenting cell with its receptor, CD28, on the T cell"

"we report the 3.2-A resolution structure of the complex between the disulphide-linked homodimer of human CTLA-4 and the receptor-binding domain of human B7-2"

"Regulation of T-cell activity is dependent on antigen-independent co-stimulatory signals provided by the disulphide-linked homodimeric T-cell surface receptors, CD28 and CTLA-4"

"T cell receptor (TCR)-interacting molecule (TRIM) is a recently identified transmembrane adaptor protein, which is exclusively expressed in T cells"

"B7-2 binds the two receptors more weakly than B7-1"

"relative to its CTLA-4 binding affinity, B7-2 binds CD28 2- to 3-fold more effectively than B7-1"

"In this study we show that CD28i, a transmembrane splice variant of CD28 costimulatory receptor, complexes with CD40L in human T cells"

"CD28i is unique among other isoforms as it retains an intact transmembrane region and cytoplasmic tail, but lacks the B7 ligand binding motif"

"Herpesvirus saimiri encodes a tyrosine kinase interacting protein (Tip) that binds to T-cell-specific tyrosine kinase Lck via multiple sequence motifs and controls its activity"

"we examined the role for CCL5-mediated initiation of mRNA translation in CD4(+) T-cell chemotaxis"

"the acquisition of suppressive behavior by activated CD4(+)CD25(-) T cells requires the expression of CTLA-4"

"Activation of human CD4(+)CD25(-) T cells resulted in the appearance of a de novo population of FoxP3-expressing cells within 48 h. These cells expressed high levels of CTLA-4"

"functional protein microarrays are particularly well-suited for high-throughput screening of extracellular protein interactions"

"MSCs with a galectin-9 knockdown lost a significant portion of their antiproliferative effects on T cells"

"CD80-Fc facilitates T cell activation by binding to PDL1 to inhibit PDL1-PD1 interactions and by costimulating through CD28"

"Cell-surface protein-protein interactions (PPIs) mediate cell-cell communication, recognition, and responses"

"we determined the dimeric helix-helix packing of CD28-TMH using nuclear magnetic resonance (NMR) technology"

"a GxxxA motif, which is highly conserved in many dimeric assemblies, is located at the dimerization interface"

"Mutating G160 and A164 can disrupt the transmembrane helix assembly and reduces CD28 enhancement in cells"

"using a high-throughput surface receptor screening method, we systematically mapped the direct protein interactions across a recombinant library that encompasses most of the surface proteins that are detectable on human leukocytes"

"CD28 signaling plays a critical role in shaping immune responses by ensuring effective T-cell activation and enhancing T-cell survival and proliferation"