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Developmental Immunology
Volume 9 (2002), Issue 3, Pages 169-172
http://dx.doi.org/10.1080/1044667031000137647

Involvement of GANP in B Cell Activation in T Cell-dependent Antigen Response

1Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo 860-0811, Kumamoto, Japan
2CREST, Japan Science and Technology Corporation (JST), Japan
3PRESTO, Japan Science and Technology Corporation (JST), Japan

Copyright © 2002 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Adaptive immunity is dependent on proliferation of antigen-driven B cells for clonal expansion in germinal centers (GCs) against T cell-dependent antigens (TD-Ag), accompanied with somatic hypermutation of variable-region gene and class switching of B cell antigen receptors. To study molecular mechanisms for B cell differentiation in GCs, we have identified and studied a 210 kDa GANP protein expressed in GC-B cells. GANP has domains for MCM3-binding and RNA-primase activities and is selectively up-regulated in centrocytes surrounded with follicular dendritic cells (FDCs) upon immunization with TD-Ag in vivo and in B cells stimulated with anti-CD40 monoclonal antibody in vitro, which suggested that GANP plays a certain important role in the maturation of immunoglobulin or selection of B cells in GC during the immune response to TD-Ag. Since this up-regulation has not been detected in T cells in GCs and in Concanavalin A-stimulated T cells in vitro, selective function of GANP molecule on B cell proliferation and differentiation might exist.