Negative feedback regulation of IgE synthesis by murine CD23.
Immunoglobulin E is found in nanogram amounts in normal human and mouse serum. It is increased during parasitic infestations and mediates allergy. CD23, the low-affinity receptor for IgE (Fc epsilon RII), has been proposed as an important regulator of IgE synthesis. The type-II transmembrane lectin CD23 is expressed in the mouse on B cells and follicular dendritic cells. In humans there are two forms of CD23 which differ in their intracellular amino-terminal 6/7 amino acids; expression of the A-form corresponds to that of murine CD23, whereas the B-form is also found on T and other haematopoietic cells. CD23 has been implicated in cellular adhesion, antigen presentation, as a growth and differentiation factor for human B, T and plasma cells, and as a signal transduction molecule (reviewed in refs 3, 8). Here we disrupt the gene coding for murine CD23 (ref. 9) to clarify the role of CD23 in vivo and find that B- and T-cell development is normal in these CD23-deficient mice. Immune responses to the helminth Nippostrongylus brasiliensis are unaffected. In contrast, immunization with thymus-dependent antigens leads to increased and sustained specific IgE antibody titres compared with controls. Formation of germinal centres is normal. These results suggest that murine CD23 acts as a negative feedback component of IgE regulation.
Yu
P
P
Max-Planck-Institut für Immunbiologie, Freiburg, Germany.
Kosco-Vilbois
M
M
Richards
M
M
Köhler
G
G
Lamers
M C
MC
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002460:Cell Line; D004140:Dinitrophenols / Q000276:immunology; D005246:Feedback; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016296:Mutagenesis; D009559:Nippostrongylus / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D017455:Receptors, IgE / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
D004140:Dinitrophenols; D017455:Receptors, IgE; C045521:dinitrophenol-ovalbumin; D007073:Immunoglobulin E; D010047:Ovalbumin