Comparative Properties of Polyclonal and Monoclonal Antibodies

This chapter was written with the express goal of introducing several basic concepts involved when antigens and antibodies interact in vitro to the novice reader and to serve as a review of these concepts to the more advanced reader. Most of these concepts also apply to in vivo reactivity. Antigen-antibody reactions in vivo frequently involve subsequent reactions of the complexes with complement, but these reactions will be largely ignored for the purpose of this chapter. Reactivity properties of antibodies are determined by several important structural features of the antigens and antibody preparations used. Major properties of antigens that influence their reactivities with antibodies include structural features such as whether individual epitopes are repeated on the molecule, the relative proportion of sequential and conformational epitopes, and the degree of purity of the antigen preparation. For purposes of this chapter, it will be assumed that the antigens used as examples are pure, but the knowledgeable reader will understand that this is almost never the case.