Immunoglobulin G; structure and functional implications of different subclass modifications in initiation and resolution of allergy

Abstract

IgE and not IgG is usually associated with allergy. IgE lodged on mast cells in skin or gut and basophils in the blood allows for the prolonged duration of allergy through the persistent expression of high affinity IgE receptors. However, many allergic reactions are not dependent on IgE and are generated in the absence of allergen specific and even total IgE. Instead, IgG plasma cells are involved in induction of, and for much of the pathogenesis of, allergic diseases. The pattern of IgG producing plasma cells in atopic children and the tendency for direct or further class switching to IgE are the principle factors responsible for long‐lasting sensitization of mast cells in allergic children. Indirect class switching from IgG producing plasma cells has been shown to be the predominant pathway for production of IgE while a Th2 microenvironment, genetic predisposition, and the concentration and nature of allergens together act on IgG plasma cells in the atopic tendency to undergo further immunoglobulin gene recombination. The seminal involvement of IgG in allergy is further indicated by the principal role of IgG4 in the natural resolution of allergy and as the favourable immunological response to immunotherapy. This paper will look at allergy through the role of different antibodies than IgE and give current knowledge of the nature and role of IgG antibodies in the start, maintenance and resolution of allergy.

New Perspectives in Food Allergy

“…The decreased reactivity of effector cells of anaphylaxis and the downregulation of their release ability and degranulationare among the early modifications induced by FAIT. Specific IgE levels are decreased by FAIT, whereas allergen-specific IgG4 are increased, competing with IgE to dampen the allergic response [143,144]. In addition, FAIT also induces anergy and functional exhaustion of other cells, probably resulting in their elimination.…”

Oral administration with a traditional fermented multi-fruit beverage modulates non-specific and antigen-specific immune responses in BALB/c mice

“…Thus, regulation of the balance between these two types of cells is considered to be essential for immune homeostasis [54]. Several studies have shown that a polarized Th2 response is often observed in patients with allergies [55,56]. Therefore, enhancing a Th1-type immune response is expected to be beneficial for the treatment of allergic disease.…”

Patterns of sensitization to inhalant and food allergens among pediatric patients from the Moscow region (Russian Federation)

“…Unlike the other IgG subclasses, IgG4 antibodies are involved in Fab-arm exchange resulting in the occurrence of antibodies with bivalent reactivity. Bispecific antibodies unable aggregate in large complexes with allergens to activate the complement system and to induce hypersensitivity reactions of types II and III [ 4 ]. That is why IgG4 presence likely leads to reduce clinical symptoms of allergy and in some cases, can indicate a tolerance to allergens [ 5 , 6 ].…”