Immunity classes

The class II cytokine receptor family includes receptors for interferon a/P (lEN a/P) and y (lENy) and IL-10. lEN-y immunoreactivity has been found in neurons in the hypothalamus, cerebral cortex, mammilary nuclei, and dorsal tegmentum. Astrocytes and microglia in vitro can be stimulated to express class II histocompatibiHty complex (MHC-II) antigens by lEN-y, which may be involved in the presentation of antigen to T-ceUs by astrocytes. Thus lEN-y may be critical in CNS-immune function and dysfunction especially in regard to neuronal and gHal apoptotic processes. 

Haptens, a special class of antigen, are small molecules that induce specific antibody production when they are attached to a protein that acts as a carrier. Phosphorylcholine is one such hapten that has been widely used in the investigation of immune responses. The specific binding of this hapten... 

The activation of DRF-3 through the TREF dependent pathway allows for chemokines such as RANTES to be produced. It also leads to the production of DFN-a and EFN-(3, which are involved in anti-viral immunity. The TREF pathway, activated by either TLR-3 or TLR-4, can also induce MHC class-II expression and costimulatory molecules, thus leading to T-cell activation. This provides an important link between innate and adaptive immunity. 

Type I allergic reactions are inappropriate immune responses to an allergen with preferential synthesis of immunoglobulin E (IgE), a special antibody class, which binds to mast cells and basophilic granulocytes via Fee receptors. Binding of the allergen to the cell-bound IgE initiates the rapid release of allergic mediators, most prominently histamine, and the de novo synthesis of arachidonic acid metabolites and cytokines, which are responsible for the clinical symptoms. 

A Type III allergic reaction occurs when antibodies of the immunoglobulin G class (IgG) form immune complexes which are slowly eliminated and thus may elicit an inflammatory reaction by binding to the Fey receptors of leukocytes resulting in their activation. 

These disorders are all acquired conditions with no evidence of an hereditary basis. Most of them involve inflammation of the skeletal muscle itself (myositis) (Figure 17), though this may sometimes occur because of initial targeting of the muscle vasculature or connective tissue. Many instances of myositis are classed as idiopathic disorders, in that the precise mechanisms of muscle degeneration are not known, but is widely accepted that these syndromes are associated with abnormal function of the immune system. The syndromes of polymyositis (PM) and derma-... 

Aguas, A., Esaguy, N., Sunkel, C.E., Silva, M.T. (1990). Cross-reactivity and sequence homology between the 65 kilodalton mycobacterial heat shock protein and human lactoferrin, transferrin, and DR beta subsets of major histocompatibility complex class II molecules. Infect. Immun. 58, 1461-1470. 

The Liskamp group also examined the ability of peptoid-peptide hybrids to be bound by the MHC Class II receptor, an important component of the human immune system [39]. Two of three peptoid substitutions in the 14-residue peptide caused substantial decreases in binding affinity, despite the fact that these were solvent-exposed residues. These results were attributed to a loss of hydrogen-bond contacts as well as to steric clashes caused by unfavorable positioning of the new side chain groups. 

Perrigoue JG, Saenz SA, Siracusa MC, Allenspach EJ, Taylor BC, Giacomin PR, Nair MG, Du Y, Zaph C, van Rooijen N, Comeau MR, Pearce EJ, Laufer TM, Artis D MHC class Il-dependent basophil-CD4+ T-cell interactions promote Th2 cytokine-dependent immunity. Nat Immunol 2009 10 697-705. 

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