Effect of solutes on the cold-induced insolubility of monoclonal cryoimmunoglobulins.

The effects of a variety of compounds upon the cold-induced insolubility of the IgM-K cryoglobulin McE have been examined. Cryoprecipitation was found to be inhibited by certain neutral salts, ureas, amides, tetraalkylammonium salts, long chain sodium alkyl sulfates, sugars, and a number of other agents. Cryoprecipitation was enhanced by increasing the hydrophobicity of alcohols, ureas, amides, and tetraalkylammonium salts, as well as by low concentrations of many solutes. With the exception of the alkyl sulfates, inhibition was not accompanied by detectable changes in conformation of the cryoimmunoglobulin. These inhibitions and enhancements were also associated with changes in the temperature at which cryoprecipitation was initiated as well as the temperature at which a low temperature-induced conformation change occurs in the McE protein. The effects of solutes on McE are compared to results obtained with five other (two IgG, three IgM) cryoimmunoglobulins, and it is hypothesized that electrostatic and dispersion forces are primarily responsible for the cold insolubility of monoclonal cryoimmunoglobulins.