IgG Isolation via Flow-Through Ion Exchange
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Solution Overview
Problem
Current methods for isolating immunoglobulin G (IgG) from plasma face challenges such as low yield, high contamination, and process inefficiencies, including rapid fouling of diafiltration membranes and protein loss during ion exchange steps.
Innovation Solution
The method involves successive ion exchange steps where IgG remains in flow-through fractions, avoiding elution steps, and using salt fractionation to separate supernatants and precipitates, followed by anion and cation exchange media to achieve high purity and yield, with a depth filter to retain contaminants like Factor XI, resulting in a 70% or more yield of IgG.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ion exchange chromatography with binding and elution steps is used, then IgG can be purified, but protein loss occurs during binding and elution
Solution Approach 1:
Instead of binding IgG to ion exchange media and then eluting it (conventional approach), the patent inverts the approach by using ion exchange media to selectively bind contaminants while IgG remains in the flow-through fraction. This inversion eliminates the elution step that causes protein loss and simplifies the process while maintaining high purity and yield
2Ease of manufacture
If diafiltration membranes are used for buffer exchange in citrate salt fractionation process, then buffer exchange can be performed, but membranes foul rapidly limiting scale
Solution Approach 1:
The patent extracts and eliminates the problematic diafiltration membrane step from the process. Instead of using membranes that foul rapidly, the invention uses a combination of depth filtration and ion exchange chromatography to achieve buffer exchange and purification, allowing the process to be scaled up without membrane fouling limitations
3Manufacturing precision
If Cohn process is used for IgG isolation, then IgG can be separated from plasma, but yield is only 50-60% and process takes 7-10 days
Solution Approach 1:
The patent fundamentally changes the separation parameters from the Cohn process by using ion exchange chromatography based on electrical charge rather than ethanol-based fractionation based on solubility. This parameter change enables a much faster process (2 days vs. 7-10 days) while achieving higher yields through the flow-through collection method that prevents protein loss
4Manufacturing precision
If ion exchange chromatography is used to remove contaminants, then purity increases, but IgG is bound and lost during the process
Solution Approach 1:
The patent applies the inversion principle by reversing the target of ion exchange binding. Instead of binding IgG and losing it during elution, the ion exchange media is used to bind contaminants while IgG passes through in the flow-through fraction, achieving both contaminant removal and high IgG recovery without binding loss
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process significantly increases IgG yield to 75% or more, reduces contamination, and simplifies processing, while maintaining high purity and stability, with a reduced processing time of approximately two days compared to traditional methods.
Implementation Method 1
adding a salt (such as a citrate or acetate salt) to the solution to generate a supernatant and a precipitate
Implementation Method 2
applying the dissolved precipitate to an anion exchange media to generate a first bound fraction and a first flow-through
Implementation Method 3
applying the first flow-through to a cation exchange media that can bind both the protein and the contaminant to generate a second bound fraction that includes the contaminant and a second flow-through that includes the protein
Implementation Method 4
a depth filter that is selected to retain Factor XI and/or Factor XII
Data Source
AI summary
Systems are provided for isolation of a protein, such as immunoglobulin G (IgG), from plasma, where the protein is initially fractioned by salt precipitation, followed by successive ion exchange steps in which the protein appears in unbound, flow-through fractions of the ion exchange steps. Some embodiments employ successive anion exchange steps. Other embodiments employ an anion exchange step followed by application of flow-through of the anion exchange step to a cation exchange step, with the protein collected in flow-through fractions from the cation exchange step. IgG is collected at high yield (typically about 75% or greater) and high purity. Avoidance of binding and elution from chromatography media simplifies processing and scale up without sacrificing IgG quality or yield.