Treatment of antibodies with the enzyme papain under conditions of limited proteolysis results in hinge-region cleavage,yielding monovalent antigen-binding Fab fragments that lack a constant region.Which effector function of antibodies would Fab fragments be able to perform?

Question

Quizplus · Accepted Answer

Fab fragments lack the Fc constant region and are therefore not recognized by immune effector cells or complement.In addition,they are monovalent and therefore are incapable of cross-linking antigen.However,Fab fragments are able to bind and neutralize toxins and inhibit the activity of pathogens by compromising the function of cell-surface proteins.These effects,called "neutralization" of pathogens,are the only mechanisms of antibody action that depend solely on antigen binding.

Treatment of Antibodies with the Enzyme Papain Under Conditions of Limited