T helper type 2 cells

As with UC, the immune activation seen in CD involves the release of many proinflammatory cytokines. Cytokines thought to play major roles in CD are derived from T-helper type 1 cells and include interferon-y, TNF-a, and IL-1, IL-6, and IL-12. TNF-a is a major contributor to the inflammatory process seen in CD. Its physiologic effects include activation of macrophages, procoagulant effects in the vascular endothelium, and increases in production of matrix metallo-proteinases in mucosal cells.9,15 Excessive production of both... 

TDO TE TEC Teff TE TG TGE Thl Th2 TIA d yptophan 2,3-dioxygenase echo time thymic epithelial cell T effector cells d anscripdon factor digeminal ganglia d ansforming growth factor T helper type 1 cell T helper type 2 cell d ansient ischemic attack VI VAMP VCAM primary visual cortex vesicle-associated membrane protein vascular cell adhesion molecule... 

Interleukin-12 (IL-12) is a heterodimeric cytokine produced by phagocytic cells, B cells, and other antigen-presenting types of cells. It is a potent inducer of cytokine production, causes T and NK cells to secrete IFN-y, is a growth factor for preactivated T and NK cells, and enhances cytotoxic activity in CDS T cells and NK cells. It also has a role in the generation of T helper type 1 cells and in the differentiation of cytotoxic T lymphocytes. ... 

Mencacci A, Del Sero G, Cenci E, d Ostiani CF, Bacci A, Montagnoli C, Kopf M, Romani L Endogenous interleukin 4 is required for development of protective CD4+ T helper type 1 cell responses to Candida albicans. J Exp Med 1998 187 307-317. 

Murphy TL, Murphy KM, Weaver CT Interleukin-17-producing CD4+ effector T cells develop via a lineage distinct from the T-helper type 1 and 2 lineages. Nat Immunol 2005 6 1123-1132. 

Chipeta, J., et al. CD4+ and CD8+ cell cytokine profiles in neonates, older children, and adults increasing T helper type 1 and T cytotoxic type 1 cell populations with age, Cell. Immunol., 183, 149, 1998. 

Dahl ME, Dabbagh K, Liggitt D, Kim S, Lewis DB Viral-induced T helper type 1 responses enhance allergic disease by effects on lung dendritic cells. Nat Immunol 2004 5 337-343. 

Tjjl cells (i.e. T helper type 1 lymphocytes) are the cellular population that triggers a cell-mediated immune response. This is the most effective means by which the immune system can identify and destroy many foreign agents, particularly viruses, bacteria or parasites, that have entered host cells. 

Fig. 9.2. Simplified schema of the development of T helper type 1 (Th1) and 2 (Th2) cells under the influence of interleukin (IL)-12 and IL-4, respectively, and how these two polarized T cell phenotypes produce cross-inhibitory cytokine profiles and promote different aspects of the host immune response (IFNy, interferon-gamma TNFa, tumour necrosis factor alpha Thr, T helper regulatory cell Th3, T helper type 3 cell).

Immunotoxicity of Oligonucleotide Therapeutics The pro-inflammatory activity of the ASOs produces a constellation of effects, which includes splenomegaly, lymphoid hyperplasia, and multi-organ lymphohistiocytic cell infiltrate driven by the production of pro-inflammatory cytokines [57,63,75]. Incorporation of immunostimulatory sequences like unmethylated CG dinucleotides mimic bacterial DNA [76], Unmethylated CG dinucleotides interact with receptors of the innate immune system such as TLR9 to produce a shift toward T-helper type 1 immunity [77,78], Oligonucleotides with these motifs modulate the immune system. We have recently reported on a direct evaluation for effects on immune function. 

The sympathetic nervous system innervates the major lymphoid organs such as the spleen with nerve fibers reaching both the vasculature and the parenchyma where lymphocytes, primarily T cells (T helper type 1-2, T l, T j2), reside (Friedman and Irwin, 1997). T cells possess receptors for both norepinephrine and neuropeptide Y that are released in response to sympathetic nerve stimulation. The adrenergic receptors are primarily the subtype, which is consistent with data demonstrating that (32 agonists can markedly influence the immune system (Kohm and Sanders, 2001). For example, stimulation of T cell receptors results in increased cyclic AMP formation, which can modulate cytokine expression, i.e., decreasing... 

Yssel, H, Shanafelt, M.C., Soderbetg, C., Schneider, P.V. Anzola, J. and Peitz, G. (1991). Borrelia bui dorferi activates a T helper type 1-like T cell subset in lyme arthritis. J. Exp. Med. 174, 593-601. 

Manetti, R., Parronchi, P., Giudizi, M.G., Piccinni, M.P., Maggi, E, Trinchieri, G. and Romagnani, S. (1993). Natural killer cell stimulatory factor (interleukin 12 [IL-12]) induces T helper type 1 (THl)-specific immune responses and inhibits the development of IL-4-producing Th cells. J. Exp. Med. 177, 1199-1204. 

Munoz, E., Beutner, U., Zubiaga, A. and Huber, B.T. (1990a). IL-1 activates two separate signal transduction pathways in T helper type II cells. J. Immunol. 144, 964-969. 

Barrat, F.J. etal. (2002) fra vitro generation of interleukin 10-produdng regulatory CD4+ T cells is induced by immunosuppressive drugs and inhibited by T helper type 1 (Thl)- and Th2-inducing cytokines. The Journal... 

McGuirk P, McCann C, Mills KH Pathogen-specific T regulatory 1 cells induced in the respiratory tract by a bacterial molecule that stimulates interleukin 10 production by dendritic cells a novel strategy for evasion of protective T helper type 1 responses by Bordetella pertussis. J Exp Med 2002 195 221-231. 

SCHMITT, E HOEHN, P, HUELS, C GOEDERT, S PALM, N RUDE, E. GERMAN, T. (1994) T helper type 1 development of naive CD4+ T cells requires the coordinate action of interleukin-12 and interferon-y and is inhibited by transforming growth factor-. European Journal of Immunology, 24, 793-798. 

Okamoto, Y., Abe, T., Niwa, T., Mizuhashi, S.,and Nishida,M. (1998) Developmentof a dual color enzyme linked immunospot assay for simultaneous detection of murine T helper type 1 and T helper type 2 cells. Immunopharmacology, 39, 107 116. 

The discovery of polarized subsets of CD4+ T cells that differ in their cytokine secretion pattern and effector functions has provided the molecular framework for the understanding of the diversity ofT-cell-dependent immune responses against different types of pathogens [63, 64], The two subsets of differentiated CD4+ T cells, T helper type 1 (Thl) and T helper type 2 (Th2), protect against different microbial pathogens by producing cytokines able to mobilize different mechanisms of defense. Thl cells are characterized by the secretion of interferon-y (IFN-y) and are adept at macrophage activation. 

Fig. 18.1-6 T helper cell differentiation. Thl and Th2 cells develop from a common precursor, the naYve CD4+ T cell. Nai ve CD4+ T cells differentiate into T helper type 1 and T helper type 2 (Thl and Th2) cells that protect against microbial pathogens by producing cytokines that mobilize appropriate defence mechanisms. The differentiation process is initiated by stimulation oftheT-cell receptor (TCR) on the naive CD4+ T cell with a peptide-major histocompatibility complex (MHC) complex on an antigen-presenting cell (APC).

Jacohson, NG, Szabo SJ, Weber-Nordt RM, Zhong Z, Schreiber RD, Darnell JE Jr, Murphy KM. Interleukin 12 signahng in T helper type 1 (Thl) cells involves t5Tosine phosphorylation of signal transducer and activator of transcription (Stat)3 and Stat4. J Exp Med 1995 181 1755-1762. 

Ausiello CM, Fedele G, Urbani F et al. Native and genetically inactivated pertussis toxins induce human dendritic cell maturation and synergize with lipopolysaccharide in promoting T helper Type 1 responses. J Infect Dis 2002 186(3) 351-360. 

VDH, vascular dilation and hemorrhage DTH, delayed-type hypersensitivity DT-APR, delayed-type acute phase response Thiand Th2, T helper type 1 and 2 cells NK, natural killer IL, interleukin TNF, tumor necrosis factor INF, interferon. 

Antigens commonly induce the activation of T-lymphocytes of the T helper type (Th). In the case of Type IV b reactions the predominant responding cell is the Th-1 subtype. By secreting many cytokines, including... 

Medzhitov R Basophils function as antigen-presenting cells for an allergen-induced T-helper type 2 d 1 response. Nat Immunol 2009 10 713-720. 

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