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Nonenzymatic Glycosylation of Immunoglobulin G Impairs Complement Fixation
Author(s) -
Hennessey Patrick J.,
Black C. Thomas,
Andrassy Richard J.
Publication year - 1991
Publication title -
journal of parenteral and enteral nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.935
H-Index - 98
eISSN - 1941-2444
pISSN - 0148-6071
DOI - 10.1177/014860719101500160
Subject(s) - glycation , chemistry , complement fixation test , antibody , immunoglobulin g , albumin , medicine , incubation , endocrinology , complement system , immune system , biochemistry , immunology , receptor , serology
Transient hyperglycemia in patients receiving total parenteral nutrition may be associated with impaired immune function. The effects of short‐term hyperglycemia on one aspect of antimicrobial immune function, ie, the ability of IgG to fix complement, were investigated. Aliquots of antihuman albumin, anti‐horse ferritin, and anti‐alkaline phosphatase were incubated for 0, 8, 16, 24, 48, and 96 hr with either 0 or 240 mg of glucose per deciliter of buffer. All samples were analyzed for the degree of glycation using a thiobarbituric acid assay, and for complement fixation ability using a microcomplement fixation assay. Significant increases in glycation over control samples were observed after only 16 hr (31 us 15 mmol 5‐hydroxymethylfurfural/mol IgG, p < 0.01). Complement fixation was significantly altered after 48 hr of incubation (76 ± 5% vs 90 ± 8% total serum complement fixed by albumin/antialbumin complex, p < 0.03) when four of the 84 (4.7%) IgG lysine residues were glycated. It is demonstrated that a significant reduction in complement fixation by immunoglobulin occurs with elevated glucose concentrations and that this may play a clinically significant role in transiently hyperglycemic patients. (Journal of Parenteral and Enteral Nutrition 15: 60–64, 1991)