IgG2a-mediated enhancement of antibody responses is dependent on FcRgamma+ bone marrow-derived cells

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 a...

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Bibliographic Details
Published in:Scandinavian journal of immunology 2001-11, Vol.54 (5), p.495-500
Main Authors: Diaz de Ståhl, T, Heyman, B
Format: Article
Language:English
Subjects:
Animals
Antibody Formation
Antigen-Antibody Complex - administration & dosage
Bone Marrow Cells - immunology
Cattle
Chimera - immunology
Immunization
Immunoglobulin G - administration & dosage
Immunoglobulin Isotypes - biosynthesis
Immunologic Memory
Mice
Mice, Inbred BALB C
Mice, Inbred CBA
Mice, Knockout
Mice, Nude
Receptors, IgG - genetics
Receptors, IgG - metabolism
Serum Albumin, Bovine - administration & dosage
Serum Albumin, Bovine - immunology
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Summary: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 FcgammaRI, FcgammaRIII and FcepsilonRI owing to gene targeting of the common FcRgamma subunit (FcRgamma-/-). Here we show that enhancement after immunization with BSA-TNP/IgG2a complexes is restored in irradiated FcRgamma-/- recipients transferred with wild-type (FcRgamma+/+) bone marrow (BM) cells. In contrast, no enhancement is seen in FcRgamma+/+ irradiated animals reconstituted with FcRgamma-/- BM cells. We conclude that IgG2a-mediated enhancement of Ab responses is dependent on the presence of FcgammaRI and/or FcgammaRIII on BM-derived cells and that the presence of these receptors on the radioresistant follicular dendritic cell is not essential.
ISSN:0300-9475