Hyper-Ag-specific Ab Production in NC/Nga Mice is not associated with Deletion Polymorphism in the Promotor Region of the FcγRIIB Gene
Tohru Sakai, Mariko Nakamoto and Emi Suto
DOI : 10.3844/ajisp.2009.61.64
American Journal of Immunology
Volume 5, Issue 3
Problem statement: NC/Nga (NC) mice produced high levels of ovalbumin (OVA)-specific IgG, IgG1 and IgG2a. We previously found deletion polymorphisms in the promoter region of fcgr2b in NC mice. To determine whether this mutation causes a hyper-humoral immune response, we generated congenic BALB/c mice carrying the NC-type fcgr2b allele (NC fcgr2b) and analyzed humoral immune response and FcγRIIB on germinal center (GC) B cells. Approach: BALB/c, NC and BALB/c- NC fcgr2b congenic mice were immunized with OVA 2 times at a 2-week-interval. Levels of OVA-specific IgG, IgG1 and IgG2a in serum were determined by ELISA. Four-color (anti-B220, anti-IgD, 2.4G2 and PNA) flow cytometry analysis was performed on splenocytes obtained from OVA-immunized mice and levels of FcγRIIB in GC (IgD-PNAhigh) and non-GC (IgD+PNAlow) B cells were analyzed. Results: Although perturbed up-regulation of FcγRIIB on GC B was observed in congenic mice, levels of OVA-specific Abs were comparable to those in BALB/c mice. Conclusion: NC fcgr2b affects the level of FcγRIIB in GC B cells but that the reduced FcγRIIB expression is not related to enhanced Ag-specific Ab responses in NC mice.
© 2009 Tohru Sakai, Mariko Nakamoto and Emi Suto. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.