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IgG2a‐Mediated Enhancement of Antibody Responses is dependent on FcRγ + Bone Marrow‐Derived Cells
Author(s) -
De Ståhl T. DÍaz,
Heyman B.
Publication year - 2001
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.2001.01000.x
Subject(s) - antibody , immune system , immunization , bone marrow , immunology , bovine serum albumin , antigen , microbiology and biotechnology , chemistry , b cell , biology
Antibodies (Ab) administered in complex with antigens (Ag) have the capacity to regulate the out‐coming specific immune response. Primary immunization with complexes of bovine serum albumin‐2,4,6‐trinitrophenyl (BSA–TNP) and immunoglobulin (Ig)G2a anti‐TNP induced a significant enhancement of IgG1 and IgG2a BSA‐specific Ab response compared to immunization with the Ag alone. Enhancement was absent in nude mice, demonstrating the requirement of T cells for this regulation. Secondary immunization with BSA alone in mice previously primed with BSA‐TNP/IgG2a led to a dramatic increase of Ab production, showing that immune complexes are efficient inducers of immunological memory. IgG‐mediated enhancement of Ab responses has previously been shown to be impaired in mice lacking FcγRI, FcγRIII and FcεRI owing to gene targeting of the common FcRγ subunit (FcRγ −/– ). Here we show that enhancement after immunization with BSA–TNP/IgG2a complexes is restored in irradiated FcRγ −/– recipients transferred with wild‐type (FcRγ +/+ ) bone marrow (BM) cells. In contrast, no enhancement is seen in FcRγ +/+ irradiated animals reconstituted with FcRγ −/– BM cells. We conclude that IgG2a‐mediated enhancement of Ab responses is dependent on the presence of FcγRI and/or FcγRIII on BM‐derived cells and that the presence of these receptors on the radioresistant follicular dendritic cell is not essential.