SCALE UP ISOLATION OF IMMUNOGLOBULINS FROM PIG SERUM BY IMMOBILIZED METAL AFFINITY CHROMATOGRAPHY

The immunoglobulins (Ig's) are proteins with a well‐known structure and function. In immunocompetent animals (individuals), these proteins counteract the pathogenic microorganisms. However, under pathological conditions or in a precocious weaning, exogenous immunoglobulins, among other treatments, are being used to avoid and cure some diseases. There is much interest in developing alternative methods for the isolation of functional immunoglobulins from sources different than maternal colostrum and milk. Pig serum contains a high concentration of Ig's and it has the advantage of containing not only IgG but also IgA and IgM in a greater proportion than found in any other species. Pig serum is a major contaminant generated by meat producers that could be used as a biotechnological alternative for blood or milk whey. Immunoglobulins G, A and M were isolated from porcine serum using Nickel‐Iminodiacetate‐Sepharose 6B in a single step at an analytical level. The procedure was easily scaled up to a 30 ml bed column. Serum immunoglobins (176 ml; 8.7 g) were adsorbed to the gel in buffer, pH 6.0, containing 1.0 M NaCl, and the purified immunoglobulins (735 mg) were eluted using the same buffer, but at pH 5.0. This separation was repeated 27 times without loss of gel capacity. The source of immunoglobulins, the longevity of the adsorbent, the gel capacity (29 mg/ml bed volume) and the mild conditions allowed rapid isolation of high concentrations of immunoglobulins. This method can serve as an alternative to those currently available for obtaining the three major immunoglobulins for inclusion in animal feeding.