Binding of dog immunoglobulins G, A, M, and E to concanavalin A

Lectin Affinity Chromatography: An Efficient Method to Purify Horse IgG3

Affinity chromatography is a separation method based on a specific binding interaction between an immobilized ligand and its binding partner. An important class of ligands for the effective separation and purification of biotechnologically important substances is lectins, a group of naturally occurring molecules widely found in plants that display a range of specificities to bind different sugars. As sugars are often added to proteins through the process of glycosylation, ∼1/3 of all genetically encoded proteins are glycosylated, numerous cognate pairs of lectins with glycosylation groups have been discovered. Their specific binding interactions have not only allowed the development of numerous methodological strategies involving immobilized lectins to isolate molecules of interests but also for understanding the intermolecular interactions and alterations in glycosylation during a diverse set of biological phenomena, including tumor cell metastasis, intracellular communication, and inflammation. In this chapter, we describe a basic procedure for the separation of horse antibody classes by affinity chromatography based on differences in their glycosylation patterns. This procedure has been utilized for the purification of horse IgG3 (hoIgG3) from other six Ig from equine sera in a single step by using an Artocarpus integrifolia Jacalin column. This class of antibody comprises the therapeutic fraction generated in equine for passive antibody therapy and can serve as a biomarker for patient hypersensitivity. During the course of developing the protocol, the affinity interaction constant between the huIgE-hypersensitive immunoglobulin and the purified hoIgG3 was also determined.

Purification of equine IgG3 by lectin affinity and an interaction analysis via microscale thermophoresis

The availability of purified antibodies is a prerequisite for many applications and the appropriate choice(s) for antibody-purification is crucial. Numerous methods have been developed for the purification of antibodies from different sources with affinity chromatography-based methods being the most extensively utilized. These methods are based on high specificity, easy reversibility and biological interactions between two molecules (e.g., between receptor and ligand or antibody and antigen). However, no simple techniques have yet been described to characterize and purify subclasses of immunoglobulins (Ig) from some animals of biotechnology importance such as equines, which are frequently used to produce biotherapeutic antibodies. The sera of these animals present a large number of Ig classes that have a greater complexity than other animals. The implementation of an effective protocol to purify the desired antibody class/subclasses requires meticulous planning to achieve yields at a high purity. The IgG3 subclass of equine-Ig has recently been used as antigen in a new diagnostic test for allergic responses to horse sera-based therapies. Here, we defined a simple method using Jacalin lectin immobilized on Sepharose beads to prepare highly pure equine IgG3 antibodies with a determination of the affinity constants for Jacalin lectin and horse IgG3.

Transduction of binding affinity by B lymphocytes: a new dimension in immunological regulation

To date, immunologists have operated with two primary paradigms governing the antibody response: (1) that affinity maturation is primarily dependent upon antigen-driven selection of both the germline and somatically amended repertoires, and (2) that antibody effector function is isotypically determined. The teleost model now suggests that these classical paradigms should be broadened to incorporate the ability of the B cell to transduce the strength of antigen recognition (affinity) into structural modifications of its antibody product, which, in turn, modulates the antibody's effector function. Although this relationship, thus far, has only been examined and demonstrated in the teleost, we find a number of the individual elements of this structural/functional relationship have been reported for mammalian IgM, which prompts future investigations into its universality. In sum, these findings suggest a heretofore unrecognized feature of B lymphocyte affinity discrimination, which transduces the affinity of antigen recognition into functionally modified antibodies.

Purification of antibodies by affinity chromatography

This review focusses on affinity purification of immunoglobulins, a methodology which is a powerful tool to obtain pure and intact antibodies. Affinity techniques allow antibody purification both in a single step chromatographic procedure as well as in complex purification protocols depending on the intention to use the target antibody. The purification strategies for antibodies by interaction with affinity ligands such as antibodies and Fe receptors or low molecular weight compounds are described.