Abstract Upon infection or immunization, dendritic cells (DCs) present antigens (Ags) to naïve CD4 +T cells. As a result, fraction of the responding upregulate Bcl6 and differentiate into T follicular helper (Tfh) cells, which migrate B cell follicles. Once in follicles, Tfh help promote development maintenance germinal centers (GC). Importantly, limiting number is critical for maintaining sele...

A sensitive, specific, and reproducible in vitro helper assay is described which is suited to limiting dilution analysis of murine B cells. 1 in about 3,000 syngeneic splenic B cells can be induced to form plaque-forming cells (PFC) to sheep erythrocytes in this system. The induction of PFC is absolutely dependent on antigen and specific helper T cells.

Responder and nonresponder mice primed with poly-(L-glutamic acid,L-lysine,L-phenylalanine) (GLPhe), the response to which is under the control of immune response (Ir) genes, were used as a source of both types of helper T cells required for a T15 idiotype dominated T-dependent anti-phosphorylcholine (PC) response. It was found that the activity of one of the helper T cells needed for an anti-P...

Signal transduction in response to ligand recognition by T cell receptors regulates T cell fate within and beyond the thymus. Herein we examine the involvement of the CD4 molecule in the regulation of T helper cell survival. T helper cells that lack CD4 expression are prone to apoptosis and show diminished survival after adoptive transfer to irradiated recipients. The helper lineage in CD4(-/-)...

Background: Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease. Emerging data suggests that T helper 17 (Th17) cells play a pathogenic role in SLE and the increased number of these cells correlates with disease activity. In recent years, 1α, 25-dihydroxyvitamin D3 (1,25VitD3) has been considered as an immunomodulatory factor. Objective: To investigate the effect of 1,25VitD3...

Helper T cells play a crucial role in the induct ion and amplification of humoral and T cell-mediated immune responses in man. For example, helper T cells are absolutely required for the polyclonal immunoglobul in response triggered by pokeweed mitogen (PWM) (1) as well as for antigen-specific an t ibody responses to virus (2), soluble proteins (3), hapten (4), and heterologous erythrocytes (5)...

sarcoidosis is a systemic granulomatous disorder of unidentified etiology, with a heterogeneous clinical presentation. it is characterized by a reduced delayed-type hypersensitivity to tuberculin and common antigens. the balance between th1, th17 and regulatory t(treg) cells controls t-cell proliferation and activation.the th17/treg ratio in the peripheral blood and bronchoalveolar lavage fluid...