期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2012
卷号：109
期号：39
页码：15882-15887
DOI：10.1073/pnas.1206567109
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Cell surface Fc receptor for IgM antibody (FcR) is the most recently identified member among FcRs. We determined the cellular distribution of mouse FcR and the functional consequences of Fcmr disruption. Surface FcR expression was restricted to B-lineage cells, from immature B to plasma cells, except for a transient down-modulation during germinal center reactions. Fcmr ablation had no significant effect on overall B- and T-cell development, but led to a reduction of marginal zone B cells and an increase in splenic B1 B cells. Preimmune serum IgM in mutant mice was significantly elevated as were natural autoantibodies. When immunized with live attenuated pneumococci, mutant mice mounted robust antibody responses against phosphorylcholine, but not protein, determinants compared with wild-type mice. By contrast, upon immunization with a hapten-carrier conjugate, nitrophenyl-coupled chicken {gamma}-globulin (NP-CGG), the mutant mice had a diminished primary IgG1 response to both NP and CGG. These findings suggest that FcR has an important role in IgM homeostasis and regulation of humoral immune responses.
