Distinct gene expression profiles in different B-cell compartments in human peripheral lymphoid organs.
BACKGROUND
There are three major B-cell compartments in peripheral lymphoid organs: the germinal center (GC), the mantle zone (MNZ) and the marginal zone (MGZ). Unique sets of B-cells reside in these compartments, and they have specific functional roles in humoral immune response. MNZ B cells are naive cells in a quiescent state and may participate in GC reactions upon proper stimulation. The adult splenic MGZ contains mostly memory B cells and is also known to provide a rapid response to particulate antigens. The GC B-cells proliferate rapidly and undergo selection and affinity maturation. The B-cell maturational process is accompanied by changes in the expression of cell-surface and intracellular proteins and requires signals from the specialized microenvironments.


RESULTS
We performed laser microdissection of the three compartments for gene expression profiling by cDNA microarray. The transcriptional program of the GC was dominated by upregulation of genes associated with proliferation and DNA repair or recombination. The MNZ and MGZ showed increased expression of genes promoting cellular quiescence. The three compartments also revealed distinct repertoires of apoptosis-associated genes, chemokines and chemokine receptors. The MNZ and GC showed upregulation of CCL20 and CCL18 respectively. The MGZ was characterized by high expression of many chemokines genes e.g. CXCL12, CCL3, CCL14 and IFN-associated genes, consistent with its role in rapid response to infections. A stromal signature was identified including genes associated with macrophages or with synthesis of extracellular matrix and genes that influenced lymphocyte migration and survival. Differentially expressed genes that did not belong to the above categories include the well characterized BCL6 and CD10 and many others whose function is not known.


CONCLUSIONS
Transcriptional profiling of B-cell compartments has identified groups of genes involved in critical molecular and cellular events that affect proliferation, survival migration, and differentiation of the cells. The gene expression study of normal B-cell compartments may additionally contribute to our understanding of the molecular abnormalities of the corresponding lymphoid tumors.
Shen
Yulei
Y
Department of Pathology, Eppley Cancer Institute, University of Nebraska Medical Center, Omaha, NE, USA. ylshen@unmc.edu
Iqbal
Javeed
J
Xiao
Li
L
Lynch
Ryan C
RC
Rosenwald
Andreas
A
Staudt
Louis M
LM
Sherman
Simon
S
Dybkaer
Karen
K
Zhou
Guimei
G
Eudy
James D
JD
Delabie
Jan
J
McKeithan
Timothy W
TW
Chan
Wing C
WC
D017209:Apoptosis / Q000235:genetics; D016175:B-Lymphocyte Subsets / Q000737:chemistry / Q000378:metabolism; D001402:B-Lymphocytes / Q000737:chemistry* / Q000378:metabolism*; D002451:Cell Compartmentation / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics; D049109:Cell Proliferation; D018925:Chemokines / Q000235:genetics; D016207:Cytokines / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D007834:Lasers; D008221:Lymphoid Tissue / Q000737:chemistry* / Q000378:metabolism*; D042282:Microdissection / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D019707:Receptors, Chemokine / Q000235:genetics; D018121:Receptors, Cytokine / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D017154:Stromal Cells / Q000737:chemistry / Q000378:metabolism
D018797:Cell Cycle Proteins; D018925:Chemokines; D016207:Cytokines; D016326:Extracellular Matrix Proteins; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine