TY - JOUR
T1 - AID-expressing germinal center B cells cluster normally within lymph node follicles in the absence of FDC-M1+ CD35+ follicular dendritic cells but dissipate prematurely
AU - Boulianne, Bryant
AU - Le, Michael X.
AU - Ward, Lesley A.
AU - Meng, Lingjin
AU - Haddad, Dania
AU - Li, Conglei
AU - Martin, Alberto
AU - Gommerman, Jennifer L.
PY - 2013/11/1
Y1 - 2013/11/1
N2 - Upon activation with T-dependent Ag, B cells enter germinal centers (GC) and upregulate activation-induced deaminase (AID). AID+ GC B cells then undergo class-switch recombination and somatic hypermutation. Follicular dendritic cells (FDC) are stromal cells that underpin GC and require constitutive signaling through the lymphotoxin (LT) β receptor to be maintained in a fully mature, differentiated state. Although it was shown that FDC can be dispensable for the generation of affinity-matured Ab, in the absence of FDC it is unclear where AID expression occurs. In a mouse model that lacks mature FDC, as well as other LT-sensitive cells, we show that clusters of AID+PNA+GL7+ Ag-specific GC B cells form within the B cell follicles of draining lymph nodes, suggesting that FDC are not strictly required for GC formation. However, later in the primary response, FDC-less GC dissipated prematurely, correlating with impaired affinity maturation. We examined whether GC dissipation was due to a lack of FDC or other LTβ receptor-dependent accessory cells and found that, in response to nonreplicating protein Ag, FDC proved to be more critical for long-term GC maintenance. Our study provides a spatial-temporal analysis of Ag-specific B cell activation and AID expression in the context of a peripheral lymph node that lacks FDC-M1+ CD35+ FDC and other LT-sensitive cell types, and reveals that FDC are not strictly required for the induction of AID within an organized GC-like environment.
AB - Upon activation with T-dependent Ag, B cells enter germinal centers (GC) and upregulate activation-induced deaminase (AID). AID+ GC B cells then undergo class-switch recombination and somatic hypermutation. Follicular dendritic cells (FDC) are stromal cells that underpin GC and require constitutive signaling through the lymphotoxin (LT) β receptor to be maintained in a fully mature, differentiated state. Although it was shown that FDC can be dispensable for the generation of affinity-matured Ab, in the absence of FDC it is unclear where AID expression occurs. In a mouse model that lacks mature FDC, as well as other LT-sensitive cells, we show that clusters of AID+PNA+GL7+ Ag-specific GC B cells form within the B cell follicles of draining lymph nodes, suggesting that FDC are not strictly required for GC formation. However, later in the primary response, FDC-less GC dissipated prematurely, correlating with impaired affinity maturation. We examined whether GC dissipation was due to a lack of FDC or other LTβ receptor-dependent accessory cells and found that, in response to nonreplicating protein Ag, FDC proved to be more critical for long-term GC maintenance. Our study provides a spatial-temporal analysis of Ag-specific B cell activation and AID expression in the context of a peripheral lymph node that lacks FDC-M1+ CD35+ FDC and other LT-sensitive cell types, and reveals that FDC are not strictly required for the induction of AID within an organized GC-like environment.
UR - http://www.scopus.com/inward/record.url?scp=84885977788&partnerID=8YFLogxK
U2 - 10.4049/jimmunol.1300769
DO - 10.4049/jimmunol.1300769
M3 - Article
C2 - 24068672
AN - SCOPUS:84885977788
VL - 191
SP - 4521
EP - 4530
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 9
ER -