Cross/Tangential Flow Filtration of Antisera on an Industrial Scale
Kathleen M Holland MD1 and Cassandra Nicole Fuller1
Purification of antisera, on an industrial scale, to date has been performed by SEC or affinity chromatography, both of which are costly. The method of cross/tangential flow filtration feeds solution across a filter surface rather than pushing product through it. Cross flow membranes are currently used in the manufacturing of serum proteins in order to dialyze and/or concentrate these solutions. Solvent, solutes, and particles smaller than the membrane’s pore size pass through the membrane, while larger molecules are retained and concentrated. This study was designed to apply membrane purification to increase the titers of polyclonal antisera on an industrial scale, as an alternative method to traditional chromatography techniques. Membranes with varying molecular weight cut offs were used to filter and concentrate neat antisera. The reduction of serum fluids and salts increase the concentration of antibodies, and therefore raise the titers. Concentrated antisera titers were then compared to neat antisera titers, to determine if a significant increase or decrease occurred, or if the method had no effect. This method has a marked resemblance to SEC, but without the need for buffers; other characteristics of the antisera remain unchanged. As the current availability of purified polyclonal antisera is scarce, the goal of this study was to produce a more effective product for use in immunology and medical device research and manufacturing across multiple testing platforms, by producing antisera with higher titers. This could potentially result in being able to process antisera to higher titers using lower concentrations of antigen in the host species, which is important from an industrial perspective for reducing manufacturing costs.