Isolation of murine and human immunoglobulin M and murine immunoglobulin D

This unit describes two classical protocols for the purification of IgM - dialysis of ascites fluid, tissue culture medium, or bioreactor supernatants against distilled water to precipitate pure IgM, and ammonium sulfate precipitation. Both protocols can be followed by size-exclusion chromatography to obtain a highly purified product. Recently, an affinity method for purification of IgM has been developed using mannan-binding protein, and is described here. The third approach presented is a one-step IgD purification method, designed specifically for murine derived samples, that uses Sepharose coupled to lectin derived from the seeds of Griffonia simplicifolia-1. This represents a simple, rapid, and gentle, approach to isolating this highly labile immunoglobulin from IgD-containing ascites or hybridoma sources.