[The structure of carbohydrate chains of human IgG4-paraproteins differing in the ability to bind cell receptors].

Comparative oligosaccharide analysis by HPLC revealed structural differences in the carbohydrate chains of human IgG4 paraproteins, varying in ability to induce the rhesus monkey's passive skin anaphylaxis. An atypical IgG4 paraprotein, which is inactive in this reaction and also does not bind the IgG4-subclass specific monoclonal antibody IH2, has a much higher proportion of the carbohydrate chains lacking terminal galactose residues than two typical IgG4 paraproteins. This structural feature may be one of the reasons for the atypical IgG4 not to bind by the mast cell Fc gamma receptor.