THE JOURNAL OF INFECTIOUS DISEASES. VOL. 134, © 1976 by the University of Chicago. All rights reserved.
xo, 4 • OCTOBER 1976
MAJOR ARTICLES Quantitation of Serum Antibodies to Surface Antigens of Neisseria gonorrhoeae with Radiolabeled Protein A of Staphylococcus aureus From the Department of Gynecology and Obstetrics and the Institute of Medical Microbiology. University Hospital, Lund, Sweden
Karen Kvist Christensen, Poul Christensen, Per-Anders Mttrdh, and Lars Westrom
Several methods, including complement fixation, passive hemagglutination, indirect immunofluorescence, immunodiffusion, flocculation, and bactericidal tests have been used for demonstration of antibodies to Neisseria gonorrhoeae [1]. Attempts to increase the sensitivity of these tests have been accompanied by a lower specificity [1], mainly because the antigen preparations used contained many different gonococcal antigens and because cross-reactions with other species of Neisseria are common. Magnusson and Kjellander [2] and Watt et al. [3] used heated whole organisms. Danielsson et al. [4] tested purified antigens from gonococcal protoplasm and obtained multiple precipitin bands in gel diffusion tests with hyperimmune rabbit serum. Gonococcal endotoxin, used in passive hemagglutination tests, has also shown antigenic heterogenicity [5], as
have preparations of gonococcal pili antigen [6]. This report concerns the quantitation of antibodies to N. gonorrhoeae with the use of protein A from Staphylococcus aureus. Protein A reacts with the Fc part of IgG [7] of subclasses 1, 2, and 4, but not to that of subclass 3 [8]. Gonococci were mixed with human serum, and immunoglobulins, attached to the surface of the gonococci by their antibody-combining sites (Fab) were quantitated with 125I-Iabeled protein A. This principle was first employed for assay of IgG antibodies in tissues and on cell surfaces [9]. The method allows a more precise quantitation of human IgG antibodies than does other methods. Materials and Methods
Serum specimens. The following serum specimens were investigated: six sera with titers of antibody to N. gonorrhoeae of ====1 :30 and six sera with titers of
xo, 4 • OCTOBER 1976
MAJOR ARTICLES Quantitation of Serum Antibodies to Surface Antigens of Neisseria gonorrhoeae with Radiolabeled Protein A of Staphylococcus aureus From the Department of Gynecology and Obstetrics and the Institute of Medical Microbiology. University Hospital, Lund, Sweden
Karen Kvist Christensen, Poul Christensen, Per-Anders Mttrdh, and Lars Westrom
Several methods, including complement fixation, passive hemagglutination, indirect immunofluorescence, immunodiffusion, flocculation, and bactericidal tests have been used for demonstration of antibodies to Neisseria gonorrhoeae [1]. Attempts to increase the sensitivity of these tests have been accompanied by a lower specificity [1], mainly because the antigen preparations used contained many different gonococcal antigens and because cross-reactions with other species of Neisseria are common. Magnusson and Kjellander [2] and Watt et al. [3] used heated whole organisms. Danielsson et al. [4] tested purified antigens from gonococcal protoplasm and obtained multiple precipitin bands in gel diffusion tests with hyperimmune rabbit serum. Gonococcal endotoxin, used in passive hemagglutination tests, has also shown antigenic heterogenicity [5], as
have preparations of gonococcal pili antigen [6]. This report concerns the quantitation of antibodies to N. gonorrhoeae with the use of protein A from Staphylococcus aureus. Protein A reacts with the Fc part of IgG [7] of subclasses 1, 2, and 4, but not to that of subclass 3 [8]. Gonococci were mixed with human serum, and immunoglobulins, attached to the surface of the gonococci by their antibody-combining sites (Fab) were quantitated with 125I-Iabeled protein A. This principle was first employed for assay of IgG antibodies in tissues and on cell surfaces [9]. The method allows a more precise quantitation of human IgG antibodies than does other methods. Materials and Methods
Serum specimens. The following serum specimens were investigated: six sera with titers of antibody to N. gonorrhoeae of ====1 :30 and six sera with titers of
