Isolation and characterization of IgG_2a‐reactive autoantibodies from influenza virus‐infected BALB/c mice

Abstract

Repeated influenza virus infection induces the production of dominantly IgG2a-type virus-specific antibodies as well as the appearance of IgG2a-reactive autoantibodies in BALB/c mice characterized by low spontaneous rheumatoid factor-type autoantibody production. IgG2a-reactive autoantibody-producing hybridomas could be isolated from the spleen of influenza virus-infected BALB/c mice. The mAb produced by these clones represent not only IgM but also IgG and IgA isotypes and show strong isotype or isoallotype specificity. The common functional property of these autoantibodies is their preferential- and high-affinity binding to complexed, solid-phase-bound or heat-aggregated IgG2a when compared to native soluble or cell-bound IgG2a. The mechanism of induction and the possible biological function of these autoantibodies are discussed in the light of their fine specificity and functional properties.

The antigen-binding domain of a human IgG-anti-F(ab′)2 autoantibody

“…This possibility is supported by previous experiments in animals, demonstrating that some natural anti-IgG antibodies preferentially bind to antigen-complexed IgG or selectively suppress B cells whose membrane Ig is occupied by its ligand (42,56).…”

Natural Anti-Immunoglobulin Autoantibodies: Irrelevant By-Products or Immunoregulatory Molecules?

“…Alternatively, the Abs may bind to antigenbound IgG (immune complexes) but not to free IgG. This Terness/Opelz possibility is supported by experiments demonstrating that some natural anti-IgG Abs preferentially bind to antigencomplexed IgG and selectively suppress B cells whose membrane Ig is occupied by its ligand [60,73].…”

Antibodies Use Heme as a Cofactor to Extend Their Pathogen Elimination Activity and to Acquire New Effector Functions

“…F(abЈ) 2 fragments from polyclonal IgG were obtained by pepsin hydrolysis and chromatography on protein G-Sepharose (Amersham Biosciences). Z2 hybridoma that produced a mouse IgG2b antibody with specificity for mouse IgG2a (27) and the IP2-11-1 hybridoma producing a mouse IgG2a were kindly provided by Dr. Eva Rajnavolgyi (University of Lorand Eötvös, Budapest, Hungary). The growth of hybridomas and purification of antibodies were performed as described in Ref.…”