Isolation of horse IgG with protein A.

This study outlines a method for isolifying IgG antibodies from horse serum using a specific scientific process. The researchers suggest that this purified IgG could reduce serum-related reactions when used in serum therapy.

Method of Isolating Horse Immunoglobulins

• The researchers started with horse serum, from which they removed the fat using dextran sulfate, a substance commonly used for this purpose.
• The immunoglobulins within the serum were then precipitated using ammonium sulfate. Precipitation is a method often used in molecular biology to concentrate and separate proteins.
• Eight milligrams of the resulting preparation underwent affinity chromatography with protein A-Sepharose CL-4B. Affinity chromatography is a method of separating biochemical mixtures, in this case, aimed to specifically isolate Immunoglobulin G (IgG) antibodies.

Conditions for IgG Binding

• For all IgG subclasses to bind to the protein A, the research required a cold temperature of 4 degrees Celsius and a starting buffer with a pH of 8.0.
• Even the IgGs with low affinity were bound to the protein under these conditions.

Elution and Yield of IgG Antibodies

• The IgGs bound to the protein A were then eluted – washed off the affinity column – using a glycine buffer at pH 2.8.
• The yield of the isolated IgGs from this process was high, at about 90%.

Proposal for Use in Serum Therapy

• The researchers suggest that the isolated IgG could be used in serum therapy. Serum therapy is a type of immune therapy using antibodies from the serum of a recovered patient or animal to treat infection or poisonings.
• The benefit of using isolated IgG, as opposed to complete immunoglobulins (Igs), could reduce the amount needed and perhaps minimize serum-related reactions.