Antibodies mediated cytotoxicity

Types II and III Hypersensitivity. No simple animal models are currently available to assess Type II (antibody-mediated cytotoxicity) hypersensitivity reactions. IgE antibodies and immune complexes in the sera of exposed animals can be assayed using ELISA or RIA techniques that require the use of specific antibodies to the drug. 

According to the Gell and Coombs classification, allergy Type II is called antibody-mediated cytotoxicity . It is triggered by excessive destruction of... 

Receptor-mediated processes, including antibody-mediated cytotoxic (ADCQ pathway hepatobiliary and renal elemination of catabohzed antibody molecules (predicted)... 

Adams, S., Miller, G. T., Jesson, M. I., Watanabe,T, Jones, B., Wallner, B. P. (2004). PT-100, a small molecule dipepfi-dyl peptidase inhibitor, has potent antitumor effects and augments antibody-mediated cytotoxicity via a novel immune mechanism. Cancer Res. 64, 5471-5480. 

Starkey, J. R., Davis, W. C. and Talmadge, J. E. (1982). Immunoselection of tumor variants resistant to antibody-mediated cytotoxicity. Their immunologic and metastatic characterization. Cancer Immunol. Immunother. 14, 124-131. 

Type II antibody-mediated cytotoxic reactions and type III reactions mediated by soluble immune complexes are seen as fine hypersensitivity reactions. 

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). 

NK cells possess a receptor for Fc/and this enables them to adhere to target cells coated in antibody with the resultant destruction ofthat cell. This phenomenon is known as antibody-dependent cell-mediated cytotoxicity (ADCC). This was attributed to a separate cell population known as killer (K) cells but these have now been shown to be in effect NK cells. 

Betts, C.J. and Else, K.J. (1999) Mast cells, eosinophils, and antibody-mediated-cellular-cytotoxicity are not critical in resistance to Trichuris muris. Parasite Immunology 21, 45-52. 

Trinchieri G, De March M. Antibody-dependent cell-mediated cytotoxicity in humans. II. Energy requirement. J Immunol 1975 115(l) 256-260. 

Sheeja K, Kuttan G. (2007) Modulation of natural killer activity, antibody dependent cellular toxicity, and antibody dependent complement mediated cytotoxicity by andrographolide in normal and Ehrlich ascites carcinoma bearing mice. Integr Cancer Ther 6 66-73. 

ADCC Antibody-dependent cell-mediated cytotoxicity... 

Halothane-induced hepatitis seems to be mediated by both humoral and cell-mediated aspects of the immune system. Thus, both specific circulating antibodies and cytotoxic T lymphocytes are involved. One suggestion is that the mechanism involves antibody-dependent cell cytotoxicity (ADCC). 

ADCC Antibody Dependent Cell mediated Cytotoxicity... 

IgG Immunoglobulin G is present in lymph fluid, blood, cerebrospinal fluid and peritoneal fluid. It is composed of 2 y chains of 50 kDa and 2 L chains (k or ) of 25 kDa with a total molecular weight of 150 kDa. The functions of IgG include agglutination and formation of precipitate, passage through placenta and thus conferring immunity to fetus, opsonization, antibody-dependent cell-mediated cytotoxicity (ADCC), activation of complement, neutralization of toxins, immobilization of bacteria and neutralization of virus. 

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