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

This research presents a new method for purifying equine IgG3 antibodies using Jacalin lectin immobilized on Sepharose beads. Despite the importance of antibodies in biotechnological and therapeutic applications, purification techniques for some immunoglobulin subclasses, including equine’s IgG3, have not been sufficiently explored. This study also determines the affinity constants for both Jacalin lectin and horse IgG3.

Background of the Problem

• The scientists noted that while numerous methods exist for antibody purification, many are based on affinity chromatography, utilizing the specific biological interactions between molecules.
• However, certain animal species of biotechnological significance, such as horses, have not had simple techniques described for purifying and characterizing their immunoglobulins.
• This complexity extends to the different classes of immunoglobulins found in equine sera, which can significantly differ from those in other species.
• Efficacy in purifying the desired antibody class/subclasses requires meticulous planning and sophisticated methods to achieve high purity yields.

New Methodology for Purification

• The equine IgG3 subclass is used as an antigen in a new diagnostic test for allergic responses to horse sera-based therapies. Therefore, the purification of this subclass is extremely important.
• The researchers have developed a simple method to purify this subclass using Jacalin lectin, a plant protein known to interact with specific sugar molecules present on various glycoproteins, including immunoglobulins.
• They immobilized Jacalin lectin on Sepharose beads, which can then effectively interact with and bind the desired antibody protein, i.e., IgG3.

Affinity Constants Determination

• This study also provided quantifiable data in the form of affinity constants for both Jacalin lectin and horse IgG3.
• Affinity constants are a measure of the binding strength between two molecules—in this case, Jacalin lectin and IgG3— and they are crucial in judging the effectiveness of the new purification method.

Significance and Applications

• The refined method for purifying equine IgG3 antibodies can considerably enhance the production of biotherapeutic antibodies and diagnostics.
• The methodology and data generated in this research can be applied to develop new techniques for other immunoglobulin subclasses and animal species.