We have investigated the response of T cells to staphylococcal enterotoxin A (SEA) injections in vivo. We found that a single injection of SEA with an optimal dose of 10 microg increased the expression of both CD4 and CD8 significantly. There was expansion of SEA-reactive T cells in vivo after SEA re-injection and the time interval between injections strongly influenced the responsiveness of CD...

Interleukin-7 (IL-7) is an important survival factor for T cells. We report here for the first time that it has another important role, facilitating T-cell clonal unresponsiveness, or anergy. The anergy was induced by a 20-day coculture of activated-human CD4(+) T-cell clones with IL-7 and irradiated peripheral blood mononuclear cells without antigenic stimuli. T-cell survival, but not T-cell a...

a case of chronic mucocutaneous candidiasis due to candida albicans in a 13 yr-old boy is reported. evaluation of cell mediated immunity revealed cutaneous anergy to ppd and low level of t-lymphocytes b-cell count and immunoglobulin g (igg) were increased and there was a low level of serum iron. the patient was put under treatment with oral administration of ketoconazole and ferrus sulfate, whi...

BACKGROUND Cutaneous sensitivity to the tuberculin antigen is thought to indicate latent tuberculosis infection (LTBI). Some guidelines suggest treating end-stage renal disease (ESRD) patients for LTBI on the basis of tuberculin positivity. The prevalence of tuberculin sensitivity and cutaneous anergy in Indian patients with ESRD and the utility of the tuberculin test for predicting post-transp...

BACKGROUND When determining eligibility for isoniazid preventive therapy of human immunodeficiency virus (HIV)-infected patients, the cutoff value of the tuberculin skin test (TST) is often reduced from an induration of 10 mm in diameter to one of 5 mm in diameter to compensate for loss of sensitivity. The effectiveness of this reduction depends on the underlying mechanism: a gradual decrease i...

T cells that receive stimulation through the T cell receptor (TCR) in the absence of costimulation become anergic and are refractory to subsequent costimulation. This unresponsiveness is associated with the constitutive activation of the small G protein, Rap1, and the lack of Ras-dependent activation of ERK. Recent studies suggest that Rap1 can activate the MAP kinase kinase kinase B-Raf that i...

Using an IL-2-secreting, noncytolytic, H-Y-specific, CD8+ T cell clone, the functional consequences of Ag presentation by T cells to T cells were investigated. Incubation of the T cells with H-Y-soluble peptide led to nonresponsiveness to Ag rechallenge. This was due to the simultaneous induction of apoptosis, involving approximately 40% of the T cells, and of anergy in the surviving cells. The...

BACKGROUND Patients with human immunodeficiency virus (HIV) infection and latent tuberculosis are at substantial risk for the development of active tuberculosis. As a public health measure, prophylactic treatment with isoniazid has been suggested for HIV-infected persons who have anergy and are in groups with a high prevalence of tuberculosis. METHODS We conducted a multicenter, randomized, d...

Ag encounter in the absence of proliferation results in the establishment of T cell unresponsiveness, also known as T cell clonal anergy. Anergic T cells fail to proliferate upon restimulation because of the inability to produce IL-2 and to properly regulate the G(1) cell cycle checkpoint. Because optimal TCR and CD28 engagement can elicit IL-2-independent cell cycle progression, we investigate...

T-cell anergy is a tolerance mechanism defined as a hyporesponsive status of antigen-specific T cells upon prior antigen encounter and is believed to play a critical role in the evasion of tumor immunity and the amelioration of allogeneic transplant rejection. Molecular mechanisms in controlling T-cell anergy are less known. We show here that administration of an agonistic monoclonal antibody (...