Regulatory T cells (Tregs) control autoreactive T cells by inhibiting activation-induced proliferation and cytokine expression. The molecular mechanisms responsible for the inactivation of effector T cells by Tregs remain yet to be fully characterized. We report that T-helper cells stimulated in the presence of Tregs quickly activate NFAT1 and have increased NFAT1-dependent expression of the tr...

A requirement for helper T cells in the production of IgG antibody by B cells has been known for a long time and has been extensively studied (1-3). More recently, evidence has accumulated that there may be two classes of helper T cells for antibody production (4-6) and that T cell-T cell collaboration may be involved in the in vitro generation ofcytotoxic T lymphocytes (CTL) 1 against alloanti...

The murine model of Leishmania major infection has been an invaluable tool in understanding T helper differentiation in vivo. The initial evidence for a role of distinct CD4(+) T helper subsets in the outcome of infection was first obtained with this experimental model. The development of CD4(+) Th1 cells was associated with resolution of the lesion, control of parasite replication, and resista...

Background and Objectives: Infection with human immunodeficiency virus (HIV) results in dysregulation of the cytokine profile. A switch from a T helper 1 (Th1) to a Th2 cytokine has been proposed as an important factor in progression of HIV infection to AIDS. The aim of the present study was to assess the level of Th1 and Th2 cytokines in HIV infected individuals in order to identify t...

An RNA probe complementary to the endoglucanase 3 gene (cel-3) of Fibrobacter succinogenes S85 hybridized to chromosomal DNAs from isolates representing the genetic diversity of the genus. The probe was subsequently used to identify putative cel-3-containing clones from genomic libraries of representative Fibrobacter isolates. Comparative sequence analyses of the cloned cel-3 genes confirmed th...