title: Immune adherence of nascent hepatitis B surface antigen-antibody complexes in vivo in humans.
abstract: Upon i.v. injection into humans, pre-formed immune complexes bind complement and adhere to complement receptor type I (CR1, CD35) on erythrocytes (immune adherence). However, in most circumstances antigen and antibody react in the presence of complement; such nascent immune complexes may have properties different from pre-formed immune complexes. To define whether nascent immune complexes would also adhere to erythrocytes in vivo in humans, we studied immune complexes that formed upon i.v. injection of radiolabelled hepatitis B surface antigen (HBsAg) into immunized volunteers (eight subjects with anti-HBsAb levels ranging from undetectable to 50 U/ml.; and three control non-immune individuals). Immune complexes formed immediately in the subjects with detectable levels of specific antibody, and the clearance rate of these immune complexes correlated with the anti-HBsAb level (r = 0.78, P < 0.01). A fraction of the circulating immune complexes bound to erythrocytes in the three individuals with the highest antibody level (8-15% at 10 min). The effect of CR1 number per erythrocytes was analysed in two subjects with similar antibody levels and immune complexes clearance rates: immune adherence was higher in the subject with more CR1 per erythrocytes. The same immune complexes model studied in vitro provided similar results: a fraction of nascent immune complexes bound to human erythrocytes; this immune adherence was observed only when immune complexes formed in the presence of antibody excess, and correlated with CR1 number per erythrocytes (r = 0.99, P < 0.01). Finally, adherence of nascent HBsAg-antibody immune complexes to platelets was demonstrated in rabbits. Although immune adherence involves only a small fraction of nascent immune complexes at any given time, it may be essential for the safe disposal of large nascent immune complexes.
authors.affiliation: Clinique Medicale, Department of Medicine, Hĵpital Cantonal Universitaire, Geneva, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Madi
authors.forename: J P
authors.initials: JP
authors.lastname: Paccaud
authors.forename: G
authors.initials: G
authors.lastname: Steiger
authors.forename: J A
authors.initials: JA
authors.lastname: Schifferli
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000097:blood / Q000378:metabolism*; D001792:Blood Platelets / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood / Q000378:metabolism*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007104:Immune Adherence Reaction; D066298:In Vitro Techniques; D008297:Male; D018448:Models, Immunological; D011817:Rabbits; D017463:Receptors, Complement 3b / Q000097:blood
chemical_list: D000936:Antigen-Antibody Complex; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017463:Receptors, Complement 3b