Involvement of GANP in B cell activation in T cell-dependent antigen response.
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 210kDa 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.
Sakaguchi
Nobuo
N
Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-0811, Japan. nobusaka@kaiju.medic.kumamoto-u.ac.jp
Fujimura
Satoru
S
Kuwahara
Kazuhiko
K
D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology*; D000955:Antigens, T-Independent / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology*; D019915:DNA Primase / Q000378:metabolism; D005260:Female; D018858:Germinal Center / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D015854:Up-Regulation
D000943:Antigens, Differentiation; D000955:Antigens, T-Independent; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D000123:Acetyltransferases; C406825:MCM3AP protein, human; D019915:DNA Primase