Immunoglobulin binding immobilized

Table 4.8. Binding affinities of immunoglobulin subclasses from different species to immobilized Protein A, Protein G, Protein L, and thiophilic chromatography supports...

The complement protein, Cl q, has an 18-fold higher affinity for pentamenc IgM than IgG. This property may be used to purify IgM selectively from MAb ascites. Immobilized Cl q binds IgM at 4°C, and the immunoglobulin is eluted simply and isocratically (using the same buffer) by bringing the column to room temperature for 2 h. 

Attachment via affinity interactions. These methods are based on the high affinity of Fc receptors, such as protein A (PrA), protein G (PrG) or recombinant protein A/G, for the amino groups in the Fc region of antibodies. In these procedures, the Fc receptor is immobilized on a solid support and is the key element for the oriented immobilization of the antibody (Fig. 5b). However, not all Fc receptors have the same affinity to all IgG isotypes. PrA has been successfully used to bind the Fc portion of antibodies from many mammalian species, except for goat, sheep, cow and horse. PrG has some advantages over protein A, as it reacts with more IgG isotypes and to a lower extent with other immunoglobulins, such as human IgM and IgA. How-... 

In 1995 Schwarz et al.159 described novel heterocyclic structures able to adsorb selectively immunoglobulins. The structures contained sulfur and nitrogen. Reported ligands were 2-mercapto-pyridine,2-mercapto-pyrimidine, and mercapto-thiazoline. These structures were chemically immobilized on silica and agarose beads using epoxy-activated matrices. Binding capacities for silica based material were about 25 mg of IgG per milliliter of resin, while for agarose beads it was about 18 mg/mL. 

Nevens, J. R., Mallia, A. K., Wendt, M. W., and Smith, P. K. (1992). Affinity chromatographic purification of immunoglobulin M antibodies utilizing immobilized mannan binding protein. ]. Chromatogr. 597, 247-256. 

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