Antibodies specific for a segment of human membrane IgE deplete IgE-producing B cells in humanized mice
Hans D. Brightbill, … , Mercedesz Balazs, Lawren C. Wu
Hans D. Brightbill, … , Mercedesz Balazs, Lawren C. Wu
Published May 10, 2010
Citation Information: J Clin Invest. 2010;120(6):2218-2229. https://doi.org/10.1172/JCI40141.
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Research Article Immunology

Antibodies specific for a segment of human membrane IgE deplete IgE-producing B cells in humanized mice

Abstract

IgE-mediated hypersensitivity is central to the pathogenesis of asthma and other allergic diseases. Although neutralization of serum IgE with IgE-specific antibodies is in general an efficacious treatment for allergic asthma, one limitation of this approach is its lack of effect on IgE production. Here, we have developed a strategy to disrupt IgE production by generating monoclonal antibodies that target a segment of membrane IgE on human IgE-switched B cells that is not present in serum IgE. This segment is known as the M1′ domain, and using genetically modified mice that contain the human M1′ domain inserted into the mouse IgE locus, we demonstrated that M1′-specific antibodies reduced serum IgE and IgE-producing plasma cells in vivo, without affecting other immunoglobulin isotypes. M1′-specific antibodies were effective when delivered prophylactically and therapeutically in mouse models of immunization, allergic asthma, and Nippostrongylus brasiliensis infection, likely by inducing apoptosis of IgE-producing B cells. In addition, we generated a humanized M1′-specific antibody that was active on primary human cells in vivo, as determined by its reduction of serum IgE levels and IgE plasma cell numbers in a human PBMC-SCID mouse model. Thus, targeting of human IgE-producing B cells with apoptosis-inducing M1′-specific antibodies may be a novel treatment for asthma and allergy.

Authors

Hans D. Brightbill, Surinder Jeet, Zhonghua Lin, Donghong Yan, Meijuan Zhou, Martha Tan, Allen Nguyen, Sherry Yeh, Donnie Delarosa, Steven R. Leong, Terence Wong, Yvonne Chen, Mark Ultsch, Elizabeth Luis, Sree Ranjani Ramani, Janet Jackman, Lino Gonzalez, Mark S. Dennis, Anan Chuntharapai, Laura DeForge, Y. Gloria Meng, Min Xu, Charles Eigenbrot, Wyne P. Lee, Canio J. Refino, Mercedesz Balazs, Lawren C. Wu

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Figure 2

Human M1′/GFP knockin mouse has normal antibody responses and generates M1′+ GFP+ IgE B cells.

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Human M1′/GFP knockin mouse has normal antibody responses and generates ...
(A) Targeting scheme for insertion of human M1′ and a bicistronic GFP reporter gene in the mouse IgE locus. Human M1′ (red) is inserted into the mouse M1 exon splice acceptor site in-frame, with the M1 exon coding sequence. An IRES-GFP (green) bicistronic reporter gene is inserted 26-bases downstream of the end of the M2 exon. Wild-type and M1′ knockin (KI) mice immunized with TNP-OVA/alum have identical baseline and immunization-induced serum (B) IgE and (C) IgG1, as measured by ELISA. (D) Ex vivo culture of M1′ knockin mouse splenocytes with LPS and IL-4, but not LPS alone, induced M1′+ GFP+ B cells. Numbers indicate the percentage of CD19+ GFP+ cells and are representative of at least 3 experiments. Flow cytometry data from LPS+IL-4–stimulated cultures in the center panel was further gated on GFP vs. CD19 expression as defined by the box and analyzed for M1′ expression as indicated by the arrow to the right-hand panel. Isotype control antibody staining is shown as the gray areas, and 47H4 antibody staining for M1′ expression is shown as black lines. (E) A small population of GFP+ B cells was detectable in the mesenteric lymph nodes of N. brasiliensis–infected M1′ knockin mice. Numbers indicate the percentage of CD19+ GFP+ cells and are representative of at least 3 experiments.