Keily Littlefield

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Some bacteria that are common human pathogens produce protein toxins that are potent activators of human T lymphocytes expressing certain types of T-cell receptors. In this study we examined the ability of staphylococcal toxins to stimulate human T lymphocytes that also recognized the myelin autoantigens myelin basic protein and proteolipid protein. T-cell(More)
Immunization of experimental animals with myelin basic protein (MBP) or with specific MBP encephalitogenic determinants induces an autoimmune central nervous system (CNS) disease, experimental allergic encephalomyelitis, often studied as a model for human demyelinating disorders. This study examines the antigenic determinants of MBP recognized by human T(More)
In clinical trials, copolymer I (Cop 1) appears to reduce the number of exacerbations in early relapsing-remitting multiple sclerosis. The mechanism of this effect is uncertain, but Cop 1 also reduces the severity of experimental allergic encephalomyelitis and inhibits the response of murine myelin basic protein (MBP)-specific T cells. We tested(More)
IQGAP1 contains a domain related to the catalytic portion of the GTPase-activating proteins (GAPs) for the Ras small G proteins, yet it has no RasGAP activity and binds to the Rho family small G proteins Cdc42 and Rac1. It is thought that IQGAP1 is an effector of Rac1 and Cdc42, regulating cell-cell adhesion through the E-cadherin-catenin complex, which(More)
Human T-cell lines and clones reactive with whole human myelin were isolated from three normal subjects by in vitro sensitization techniques. The CD4+ T-cell lines were maintained in long-term culture by periodic antigen restimulation with myelin and use of interleukin-2. Although myelin basic protein (MBP) represents only about 10% of the dry weight of(More)
gamma delta T cells are over-represented in some multiple sclerosis (MS) parenchymal lesions and in the cerebrospinal fluid (CSF) of individuals with early MS. In this investigation we studied the T cell-T cell interactions between human, myelin basic protein-reactive T cells and peripheral blood mononuclear cells (PBMC) isolated from MS and control(More)
The induction of anergy in T lymphocytes generates T cells incapable of proliferation in response to a conventional antigenic stimulus. To investigate the induction and maintenance of anergy in human T cells, we used T cell-T cell presentation of myelin basic protein (MBP) or MBP synthetic peptides to induce anergy in vitro. Although anergic T cells(More)
The ADP-ribosylation factor-like (Arl) family of small G proteins are involved in the regulation of diverse cellular processes. Arl2 does not appear to be membrane localized and has been implicated as a regulator of microtubule dynamics. The downstream effector for Arl2, Binder of Arl 2 (BART) has no known function but, together with Arl2, can enter(More)
This report examines the antigen-specific inhibition of the IL-2-driven proliferation of autoantigen-reactive, human T cells. Human, myelin basic protein (MBP)-reactive CD4+ cell lines and clones were isolated and maintained in culture by use of IL-2 and periodic antigen stimulation. When freshly isolated antigen-presenting cells (APC) were present, MBP(More)