The immune system is designed to eradicate a large variety of invading pathogens with minimum immunopathology. T helper cells, also known as CD4+ T cells, may be subdivided into the T helper 1 (Th1) and the T helper 2 (Th2) subsets, which produce distinct profiles of cytokines [1,2]. These Th1 and Th2 cells have opposing roles, regulating immune responses to intracellular and extracellular path...

The polarized response of T helper-2 (Th2) lymphocytes to an allergen is considered to be the main cause of the pathogenesis of asthma. In this study, we asked a question whether M. bovis BCG mycobacteria which are known for the preferential stimulation of T helper-1 (Th1) immunity, diminish the effector functions of Th2 cells from allergic patients upon stimulation with a common house dust mit...

The paradigm of T helper-1 (Th-1) and Th-2 cells developing from non-committed naive precursors is firmly established. Th1 cells are characterized by IFNgamma production and, in mice, the selective switching to IgG2a. Conversely IL-4 production and selective switching to IgG1 and IgE characterize Th2 cells. Analysis of Th2 induction in vitro indicates that this polarization develops gradually i...

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...

BACKGROUND Inhibition of G-protein βγ (Gβγ) signaling was found previously to enhance T cell receptor (TCR)-stimulated increases in interleukin 2 (IL-2) mRNA in CD4(+) T helper cells, suggesting that Gβγ might be a useful drug target for treating autoimmune diseases, as low dose IL-2 therapy can suppress autoimmune responses. Because IL-2 may counteract autoimmunity in part by shifting CD4(+) T...

CD4(+) T cells differentiate into phenotypically distinct T helper cells upon antigenic stimulation. Regulation of plasticity between these CD4(+) T-cell lineages is critical for immune homeostasis and prevention of autoimmune disease. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stabilit...

Notch ligands and receptors have been implicated in helper T cell (Th cell) differentiation. Whether Notch signals are involved in differentiation of T helper type 1 (Th1) cells, Th2 cells, or both, however, remains unresolved. To clarify the role of Notch in Th cell differentiation, we generated mice that conditionally inactivate Notch signaling in mature T cells. Mice that lack Notch signalin...

We have described here two distinct types of carrier-specific helper T cells which act independently and synergistically to augment the B-cell response to a hapten. They are separable by passage through a nylon wool column. The first type of helper T cell, which we designate as Th1, is nylon nonadherent, and can help the response of hapten-primed B cells only if the haptenic and carrier determi...

Background: Polycystic ovary syndrome (PCOS) is considered as the most common cause of female infertility that affects 4-10% of women in the reproductive age. Previous studies have shown the role of a balanced immune response in a successful pregnancy and fertility. Objective: To investigate the T helper cells type 1 (Th1) /Th2/Th17/Treg paradigms in peripheral blood of infertile PCOS compared ...