PD-L2 expression extends beyond dendritic cells/macrophages to B1 cells enriched for V(H)11/V(H)12 and phosphatidylcholine binding.
B1 B cells are the major source of natural antibody that is essential for innate immunity. The B1 repertoire is skewed toward production of phosphatidylcholine (PtC)-binding V(H)11 and V(H)12 immunoglobulin that plays a key role in immune defense against bacterial infection. Programmed death-ligand 2 (PD-L2) is a ligand for the immunosuppressive receptor programmed death-1 (PD-1). It has been reported that expression of PD-L2 is restricted to dendritic cells and macrophages in mice. Here we show that 50-70% of resting peritoneal B1 cells express PD-L2, which is not present or inducible on conventional B2 B cells or PD-L2(-) B1 cells. Although PD-L2(+) and PD-L2(-) B1 cells are similar in proliferative responses and spontaneous immunoglobulin secretion, PD-L2(+) B1 cells are highly enriched for expression of V(H)11 and V(H)12 genes and encompass the bulk of PtC-binding B1 cells. These findings extend the range of known PD-L2 expression to B cells and show that B1 cells identified by this marker express a specific repertoire associated with anti-bacterial immunity.
Department of Medicine, Boston University Medical Center, Boston, MA, USA.
Xuemei
X
Zhong
Joseph R
JR
Tumang
Wenda
W
Gao
Chunyan
C
Bai
Thomas L
TL
Rothstein
D000818:Animals; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D010455:Peptides / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000276:immunology*; D061027:Programmed Cell Death 1 Ligand 2 Protein
D007135:Immunoglobulin Variable Region; C556978:Pdcd1lg2 protein, mouse; D010455:Peptides; D010713:Phosphatidylcholines; D061027:Programmed Cell Death 1 Ligand 2 Protein