Effector functions of antibodies

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... 

As mentioned briefly above, antibodies have multiple, complex functions. In the body, the main effector functions of antibodies include pathogen/toxin neutralization, activation of phagocytosis and antibody-dependent cellular cytotoxicity (ADCC), and complement activation. Therapeutic approaches using antibodies or antibody fragments take advantage of these natural activities. 

Activation of the complement cascade is one of the major effector functions of antibodies because it leads to cellular lysis of pathogens and to clearance of... 

Improving effector functions of antibodies for cancer treatment enhancing ADCC and CDC. Drug Des. 

Crzych, J.M., Capron, M., Bazin, H. and Capron, A. (1 982) In vitro and in vivo effector function of rat lgC2a monoclonal anti-5, mansoni antibodies. The Journal of Immunology 129, 2739-2743. 

Eichmann, K. (1974). Idiotype suppression. I. Influence of the dose and of the effector functions of anti-idiotypic antibody on the production of an idiotype. Eur. J. Immunol. 4,296-302. 

For complement-dependent cytotoxicity, a complex cascade of protein binding and cleavage occurs that culminates in final complement mediated effector functions of phagocytosis, recruitment and activation of leukocytes, and osmotic lysis. It has been reported that Rituximab (anti-CD20) utilizes a complement-dependent mechanism for tumor cell destruction [14], If the desired effect of a therapeutic antibody is complement-dependent activity, the isotype subgroup chosen should be one that binds to complement proteins (IgGl or IgG3). 

The effector function of an antibody is defined as the mediation of other host-defense mechanism besides antigen recognition. It is highly determined by the carbohydrate structure of the heavy chain. 

Another effector function is the cell-mediated cytotoxicity. Infected cells that were recognized and opsonized by specific antibodies can be lysed by natural killer cells which are the classical K cells. These properties are highly determined by the Fc part of antibodies. IgGl and IgG3 have the highest capacity for cell-mediated cytotoxicity. The effector function of an antibody is frequently used as a mean of antibody recognition. This is especially the case with bacterial proteins such as protein A and protein G that specifically interact with the same domain. Therefore purification can interfere with the antibody effector function. 

The lymphocyte populations also arise from bone marrow progenitor cells. The B lymphocytes mature or differentiate in the bone marrow before leaving to circulate in the blood and lymph, while T lymphocytes undergo maturation in the thymus. Antibodies mediating the effector functions of the... 

Fc receptors. Receptors expressed on a wide range of cells, interacting with the Fc portion of immunoglobulins belonging to various isotypes. Membrane-bound Fc receptors mediate different effector functions (endocytosis, antibody-dependent cell-mediated cytotoxicity) and induce mediator release. Both the membrane-bound and soluble forms of Fc receptors regulate antibody production of B cells. 

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