Lymphocyte-mediated type

Delayed type hypersensitivty (DTH) reactions (synonym type IV allergic reactions) are exaggerated, T-lymphocyte mediated, cellular immune reactions to foreign substances, which require one to two days to manifest clinical symptoms. 

TNpp is considered to be an important mediator in a number of T-lymphocyte-mediated autoimmune diseases, such as type 1 diabetes. Also, TNFs seem to play a pivotal role in certain autoimmune diseases, such as in the pathogenesis of RA, because transgenic mice constitutively overexpress TNF inflammatory arthritis but no systemic lupus erythematosus-like lesions. These findings in animals and humans suggest that the ambient level of TNF might have a hitherto underappreciated capacity to control the form in which autoimmunity is expressed as a specific syndrome or disease. ... 

Asthma is primarily a chronic inflammatory disorder of the airways of the lung characterized by T-helper cell type 2 (Th2)-lymphocyte-mediated immune response for which there is no known cure or primary prevention. 

Large granular lymphocytes, not belonging to either the T- or B-cell lineage. Natural killer (NK) cells are considered part of the innate defense system since, in contrast to cytotoxic T-cells, they are able to kill certain tumor cells in vitro without prior sensitization. The basal activity of NIC cells increases dramatically following stimulation with type I IFNs. In addition, NK cells display Fc-receptors for IgG and are important mediators of Antibody-Dependent-Cell-mediated-Cytotoxicity (ADCC). 

Type IV allergic reactions are cell-mediated hypersensitivity reactions which are characterized by the expansion of T lymphocytes specific for foreign substances exposed on cell surfaces. In type FVa allergic reactions, this results in the cell-mediated destruction of the cells, whereas in type FVb allergic reactions an... 

Cell-mediated immunity (CMI) is the result of the activity of many leukocyte actions, reactions, and interactions that range from simple to complex. This type of immunity is dependent on the actions of the T lymphocytes, which are responsible for a delayed type of immune response The T lymphocyte becomes sensitized... 

Antigens, however, can induce a second type of response which is known as the cell-mediated immune response. The antigenic agent stimulates the appearance of sensitized lymphocytes in the body which confer protection against organisms that have the ability to live and replicate inside the cells of the host. Certain of these lymphocytes are also involved in the rejection of tissue grafts. 

A large number of cells are involved in the immune response and all are derived fiom the multipotential stem cells of the bone marrow. The predominant cell is the lymphocyte but monocytes-macrophages, endothelial cells, eosinophils and mast cells are also involved with certain immune responses. The two types of immunity (humoral and cell-mediated) are dependent on two distinct populations of lymphocytes, the B cells and the T cells respectively. Both the humoral and the cell-mediated systems interact to achieve an effective immune response. 

Lloyd CM, Delaney T, Nguyen T, et al. CC chemokine receptor (CCR)3/eotaxin is followed by CCR4/monocyte-derived chemokine in mediating pulmonary T helper lymphocyte type 2 recruitment after serial antigen challenge in vivo. J Exp Med 2000 191(2) 265-274. 

---