Expression pattern of the human FcRH/IRTA receptors in normal tissue and in B-chronic lymphocytic leukemia.
A new family of Ig domain receptors referred to as the immune receptor translocation-associated (IRTA) proteins, FcR homologs (FcRHs) or FcR-like that are expressed in lymphoid cells has been recently described. RNA expression analysis suggests that FcRH1-5/IRTA1-5 are expressed exclusively in subsets of the B-cell compartment. We generated mAbs to FcRH1-5/IRTA1-5 and examined their protein expression pattern in normal tissue and in chronic lymphocytic leukemia (CLL) cells. Our data indicated that FcRH1-5/IRTA1-5 were expressed in B-cell sub-populations; however, in some cases, the protein was not expressed in the same B-cell populations as suggested by the RNA expression analysis. FcRH1/IRTA5 was expressed throughout the B-cell lineage starting at the pro-B-cell stage but was down-regulated in plasma cells. FcRH2/IRTA4 was expressed preferentially in memory B cells. FcRH3/IRTA3 was expressed at low levels in naive, germinal center (GC) and memory B cells but was also expressed in NK cells. FcRH4/IRTA1 was expressed in a sub-population of memory B cells associated with mucosal tissue. FcRH5/IRTA2 was expressed in mature B cells and memory B cells and down-regulated in GC cells and, unlike all other B-cell-specific markers, maintained its expression in plasma cells from tonsil, spleen and bone marrow. We examined the expression of FcRH1-5/IRTA1-5 on the surface of CLL cells and found a similar pattern of expression on CLL cells as in the normal mature B cells, except for FcRH3/IRTA3 which was up-regulated in CLL.
Polson
Andrew G
AG
Department of Translational Oncology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA. polson@gene.com
Zheng
Bing
B
Elkins
Kristi
K
Chang
Wesley
W
Du
Changchun
C
Dowd
Patrick
P
Yen
Lulu
L
Tan
Christine
C
Hongo
Jo-Anne
JA
Koeppen
Hartmut
H
Ebens
Allen
A
D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007694:Killer Cells, Natural / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism*; D051379:Mice; D016133:Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D011961:Receptors, Fc; D011971:Receptors, Immunologic / Q000096:biosynthesis*
C452186:FCRLA protein, human; D011956:Receptors, Cell Surface; D011961:Receptors, Fc; D011971:Receptors, Immunologic