Characterization of a novel hemolytic activity of human IgG fractions arising from diversity in protein and oligosaccharide components.
Human IgG is a well-established multifunctional antigen specific immunoglobulin molecule of the adaptive immune system. However, an antigen nonspecific immunological function of human IgG has never been reported. In this study, human IgG was isolated using ammonium sulfate fractional precipitation and diethylaminoethanol (DEAE) cellulose 52 ion exchange chromatography, from which h-IgG and hs-IgG fractions were purified on the basis of their differential binding to rabbit anti-shrimp hemocyanin antibody (h) and rabbit anti-shrimp hemocyanin's small subunit antibody (hs), respectively. We found that h-IgG had a higher hemolytic activity than hs-IgG against erythrocytes from humans, rabbits, mice and chickens, whereas the control IgG showed negligible activity. h-IgG could interact directly with erythrocyte membranes, and this interaction was suppressed by high molecular weight osmoprotectants, showing that it may follow a colloid-osmotic mechanism. In comparative proteomics and glycomics studies, h-IgG and hs-IgG yielded 20 and 5 significantly altered protein spots, respectively, on a 2-D gel. The mean carbohydrate content of h-IgG and hs-IgG was approximately 3.6- and 2-fold higher than that of IgG, respectively, and the α-d-mannose/α-d-glucose content was in the order of h-IgG>hs-IgG>IgG. In this study, a novel antigen nonspecific immune property of human IgG was investigated, and the diversity in the protein constituents and glycosylation levels may have functional signficance.
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China.
Shaoying
S
Min
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China ; Mariculture Institute of Shandong Province, Qingdao, China.
Fang
F
Yan
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China.
Yueling
Y
Zhang
Medical College, Shantou University, Shantou, China.
Xiangqun
X
Ye
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China.
Mingqi
M
Zhong
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China.
Jinsong
J
Cao
Medical College, Shantou University, Shantou, China.
Haiying
H
Zou
Department of Biology and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China.
Jiehui
J
Chen
D000595:Amino Acid Sequence; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D000918:Antibody Specificity; D005591:Chemical Fractionation; D002645:Chickens; D004912:Erythrocytes / Q000187:drug effects*; D005947:Glucose / Q000737:chemistry; D006031:Glycosylation; D006461:Hemolysis; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D008358:Mannose / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D033561:Penaeidae; D011817:Rabbits
D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D005947:Glucose; D008358:Mannose