The recognition of a recombinant human Fc epsilon fragment by the subclasses of IgG autoanti-IgE: disproportional subclasses distribution of complexed autoantibody.
Circulating IgG autoanti-IgE is detectable in a large proportion of individuals with allergic asthma where it is suggested to be potentially involved in the removal of IgE-allergen complexes. Since such a putative role will largely be determined by the subclass profile of complexed (i.e. IgE-bound) IgG anti-IgE, a study was undertaken to determine the subclass distribution of complexed IgG anti-IgE antibody in the sera of asthmatic patients. The study exploits the heat-labile property of IgE by heating (30 min at 56 degrees C) serum to liberate bound anti-IgE, pre- and post-heated sera are then assayed for IgG subclass anti-recombinant human Fc epsilon (rFc epsilon) activities by ELISA and any heat-induced increase in antibody activity is taken as a measure of complexed anti-IgE. This has revealed a disproportionately high amount of IgG4 in complexed (but not free) IgG anti-IgE. The propensity of IgG4 to form complexes with IgE has important biological consequences, particularly with regard to the activation of C1q and Fc gamma R by other subclasses.
Shakib
F
F
Department of Immunology, University Hospital, Queen's Medical Centre, Nottingham, UK.
Mills
C S
CS
Powell-Richards
A
A
D000328:Adult; D001249:Asthma / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis / Q000276:immunology*; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000032:analysis*; D007139:Immunoglobulin epsilon-Chains / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology
D001323:Autoantibodies; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007139:Immunoglobulin epsilon-Chains; D011994:Recombinant Proteins; D007073:Immunoglobulin E