Th2 helper cells

T-helper cells of atopic people are largely of the Th2 type rather than the Thl that is, they will induce IgE class switching in B-cells (Th2) rather than IgG class switching (Thl). Th2 helper cells synthesise IL-4 and IL-13, which promote class switching, and release IL-5, which attracts eosinophils and other inflammatory cells to the site, producing the late phase of the response. 

TH2 helper cells Pro-Inflammatory Activation of macrophages Produces lnterleukln-2 (IL-2), interferon-y (IFN-y), IL-3, TNF-a, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage chemotactic factor (MCF), migration inhibitor factor (MIF) Induce lgG2a CD4+... 

Roy S, Cain KJ, Chapin RB, Charboneau RG, Barke RA (1998) Morphine modulates NF kappa B activation in macrophages. Biochem Biophys Res Commun 245 392-396 Roy S, Wang J, Gupta S, Charboneau R, Loh HH, Barke RA (2004) Chronic morphine treatment differentiates T helper cells to Th2 effector cells by modulating transcription factors GATA 3 and T-bet. J Neuroimmunol 147 78-81... 

Bonecchi R, Bianchi G, Bordignon PP, et al. Differential expression of chemokine receptors and chemotactic responsiveness of type 1 T helper cells (This) and Th2s. J Exp Med 1998 187 129-134. 

Sato N, Ahuja SK, Quinones M, et al. CC chemokine receptor (CCR)2 is required for langerhans cell migration and localization of T helper cell type 1 (Thl)-inducing dendritic cells. Absence of CCR2 shifts the Leishmania major-resistant phenotype to a susceptible state dominated by Th2 cytokines, b cell outgrowth, and sustained neutrophilic inflammation. J Exp Med 2000 192(2) 205-218. 

Tsuyuki, S., Tsuyuki, J., Einsle, K., Kopf, M. and Coyle, A.J. (1997) Co-stimulation through B7-2 (CD86) is required for the induction of a lung mucosal T helper cell 2 (Th2) immune response and altered airway responsiveness. Journal of Experimental Medicine 185, 1671-1679. 

It is also more or less accepted that T-cells, in particular T-helper cells (CD4+), may develop into either Thl cells or Th2 cells. By doing so, T-helper cells orchestrate the ensuing immune response by the types of cytokines they produce. Thl cells, by producing IL-12 and y-IFN, stimulate macrophages and/or cytotoxic T-cells to kill and destroy infected or malignant cells, or to initiate a delayed type hypersensitivity (DTH) reaction Th2 cells, by producing IL-4, IL-5, IL-10, IL-13, trigger B-cells to initiate antibody production. 

Stimulation for 24 hours with LPS leads to the release of interleukin-1 [3, IL-6, IL-8, TNF-a and by prolonging the incubation period from 48 to 72 hours, the whole blood model can detect the release of other lymphokines [45], including IL-2, IL-4, IL-13 and IFN-y. Skewing of the T-helper cell response to antigens can likewise be detected by evaluating the pattern of cytokine release, corresponding to a predominance of Th 1 or Th2 cytokine production. The predictive value of these approaches is currently under investigation. 

Stumbles PA, Thomas JA, Pimm CL, Lee PT, Venaille TJ, Proksch S, Holt PG Resting respiratory tract dendritic cells preferentially stimulate T-helper cell type 2 (Th2) responses and require obligatory cytokine signals for induction of Thl immunity. J Exp Med 1998 188 2019-2031. 

The last two decades have witnessed numerous studies on the role of the T-helper CD4+ T cells in the onset of the asthmatic response. These studies led to the concept that CD4+ helper cells producing (Th)-type 2 cytokines play a key role in allergic responses in susceptible individuals. Moreover, while blockade of the Th2 cytokines IL-4 and IL-13 are still under consideration for a... 

The T-helper cells are further divided into two types, T-helper 1 (ThI) and T-helper 2 (Th2) (see below for discussion). Of the total lymphocyte population in the body (approx. 10 cells), the proportion of T-cells is 50-60%, that of B-cells is 10-15% and that of natural killer cells is <10%. 

A study in mice examined immune responses following topical exposure to three allergenic diisocyanates diphenylmethane-4,4 -diisocyanate (MDI), dicyclohexyl-methane-4,4 -diisocyanate (HMDI), and isophorone diisocyanate (IPDI). Contact and respiratory sensitizers induce differential immune responses in mice characteristic of Thl and Th2 T helper cell activation, respectively. All three chemicals are contact allergens. MDI is, in addition, a known human respiratory allergen. HMDI and IPDI did not produce an immunologic response in the mouse similar to MDI. These findings suggest that HMDI has much less potential to cause respiratory sensitization in humans than does MDI ... 

B cell-receptor genes totally compromised. Thus in Omenn s syndrome, where there is a mutation in the RAG 1 or RAG 2 gene, there is a partial rearrangement of receptor genes (115). Omenn s syndrome is characterized by increased IgE levels and eosinophilia due to abnormal activated oligoclonal Th2 helper T cells requiring bone marrow transplantation (105). 

AIDS represents the classic example of immunodeficiency disease caused by extrinsic factors, in this instance the human immunodeficiency virus (HIV). This virus exhibits a strong tropism for CD4 T helper cells these become depleted, giving rise to increased frequency of opportunistic infections and malignancies in infected individuals. AIDS is also characterized by an imbalance in THl and TH2 cells, and the ratios of cells and their functions are skewed toward TH2. This results in hypergammaglobulinemia, loss of cytotoxic lymphocyte activity, and delayed hypersensitivity. 

Respiratory syncytial virus (RSV) infection is a major cause of bronchiolitis in infants, whereas influenza A infection usually manifests as an upper respiratory tract infection. The immunological responses of infants to RSV infection and influenza A infection are different. In our studies of the cytokine responses during these infections, we found that the serum concentrations of IL-4, IL-5, RANTES, and soluble intercellular adhesion molecule-1 (sICAM-1) in infants with RSV infection were significantly higher than those with influenza A infection (S8). The concentration of TNF-a in nasopharyngeal aspirates was significantly lower in infants with RSV infection. Therefore, a predominant T helper cell type 2 (Th2) cytokine and related immunological response was observed in infants with RSV infection, whereas a predominantly proinflammatory cytokine response was observed in infants with influenza A infection. This may explain the different clinical manifestations of the two viral infections in infants (S8). 

---