Antibodies Antibody effector functions

Immunoglobulins are glycoproteins. The carbohydrate moiety is attached to the heavy chain (usually the Ch2 domain) via an N-linked glycosidic bond. Removal of the carbohydrate group has no effect upon antigen binding but does affect various antibody effector functions and alters its serum half-life. 

Hodoniczky J, Zheng YZ, James DC. Control of recombinant monoclonal antibody effector functions by Fc N-glycan remodeling in vitro. BiotechnolProg 2005 21 1644-1652. 

There are five different types of heavy chains, which correspond with five different classes of antibodies. The constant region of the heavy chain is identical in all antibodies of the same class. The classes of the immunoglobulin molecules differ based on the Fc region of the heavy chain, which are responsible for the different functions performed by each class. Thus the constant region confers on each class of antibody its effector function. 

The residues not in the framework region form the loops between the p strands. These loops may vary in length and sequence among immunoglobulin chains of different classes but are constant within each class the sequence of the loops is invariant. The functions of these loops are not known, but they are probably involved in the effector functions of antibodies. When an antibody-antigen complex has been formed, signals are... 

T-c fl effector functions Antibody response T-cell effector functions... 

Administration of Tyv-specific monoclonal antibodies to rat pups already infected with intestinal larvae causes larvae in the epithelium to be expelled (Carlisle et al, 1990). Only the LI stage is susceptible to expulsion once the larva has moulted to L2 it resists the effects of the antibodies (Carlisle et al, 1990). Expulsive immunity is transferred by three IgG isotypes, F(ab )2 fragments, as well as IgM (Carlisle et al., 1991a). These findings argue against a role for Fc-mediated effector functions and imply that antibodies against Tyv can disturb the larva s niche in a direct fashion. 

Scallon, BJ. et al., Chimericanti- TNF-a monoclonal antibody cA2 binds recombinant transmembrane TNF-a and activates immune effector functions, Cytokine, 7, 251,1995. 

Fc fragment (for Fragment, crystallizable) A region of an antibody (IgG molecule) composed of two heavy chains on the C-terminal side. Fc has many effector functions (e.g., binding complement, binding to cell receptors on macrophages and monocytes, etc.) and serves to distinguish one class of antibody from another. 

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