Quantitative determination of antibody-bound labeled antigens by filtration through cellulose porous membranes
✍ Scribed by L. Borella
- Publisher
- Elsevier Science
- Year
- 1968
- Tongue
- English
- Weight
- 647 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
In the course of studies of immunological tolerance to foreign proteins it was desired to have a simple, sensitive, and rapid method for detecting and measuring isotopically labeled antigens bound to antibody, particularly in the zone of antigen excess. The procedures now available are all based on the separation of antibody/labeled antigen complexes from free labeled antigen. This has been accomplished with the following procedures: (a) quantitative precipitin reaction with labeled antigens (1) ; (5) precipitation of globulins and bound labeled antigens at 56% saturation of ammonium sulfate (2, 3) ; (c) precipitation of antibody/labeled antigen complexes by the double-antibody method using an antiglobulin antibody (4, 5) ; and (d) electrophoretic separations (6, 7).
Although these methods have obvious advantages, each is subject to imitations, such as solubility of antigen-antibody aggregates in the antigen excess zone, the requirement of an antigen soluble in ammonium sulfate at 50% saturation, the requirement of an antiglobulin antibody, or time-consuming electrophoretic procedures. Hales and Randle reported a modification of the double-antibody method for insulin immunoassay based on the property of cellulosic membranes of uniform pore size (Millipore filter) to retain the complex of labeled insulin and antiinsulin rendered insoluble by a second antibody eu -
In this communication we present a procedure, which may in some instances supersede the previously described methods, for direct, separation and quantitative determination of isotopically labeled antigen bound to antibody using the Millipore filter, but without the need of a second antibody.