Plasma protein fractionation by sequential polyacid precipitation

摘要

There is a recognized need for novel, more simplified, approaches to isolation of plasma from whole blood, as well as a need to isolate cell-free plasma fractions containing different plasma proteins. Methods are divulged for use of aqueous phase systems, formed in blood or blood containing solutions via addition of a single polymer at relatively low concentration, to effect isolation (clarification) of plasma proteins from blood cells. Methods are also divulged to replace widely used Cohn-type plasma protein fractionation which is based on sequential addition of up to 40% (v/v) ethanol and other precipitants, with simple sequential addition of a polyacid. The latter results in isolation of plasma protein fractions (i.e. fibrinogen, immunoglobulin, albumin) in sequence similar to that obtained with Cohn Fractionation and therefore may be suitable for use to reduce solvent use and solvent-related process complications in existing plasma protein purification processes. It may also support use of polymeric film based containers in novel solvent free plasma fractionation processes. The methods disclosed may also be suitable for use in smaller scale plasma protein isolation, in research and diagnostic applications. The general methodologies are robust and can function over a broad range of process variables such as temperature and pH.

主权项

1. A process for separating at least fibrinogen and immunoglobulin G from a sample of blood plasma, comprising the steps of:
a) providing a sample of blood plasma in a container; b) adding a polyacid and a salt comprising ≦50 mM sodium chloride and at least one additional salt to the blood plasma, whereby said blood plasma comprises 50-100 mmol/L of total salt at pH between 6 and 8, causing formation of a first protein precipitate that comprises a majority of the fibrinogen in said sample and recovering said first protein precipitate and a first supernatant separately; and c) adding an additional amount of a polyacid to said first supernatant, causing formation of a second protein precipitate that comprises a majority of the immunoglobulin G in said sample and a second supernatant and recovering said second protein precipitate separately, wherein the polyacid is added in an amount to give a total polyacid concentration in said first supernatant which is 5-8%; wherein said first protein precipitate comprises a concentrate of the first protein and said second protein precipitate comprises a concentrate of the second protein.