부산대학교 도서관

Plasma cell alloantigen 1 (PC1), also known as ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase 1), is an enzyme involved primarily in hydrolysis of adenosine triphosphate at the cell surface. Although the expression pattern of PC1 is relatively broad, its expression in B cells is found at significant levels only in terminally differentiated germinal center B cells, plasma cells and a subset of B‐1a cells in mice. Here we describe studies designed to determine whether expression of PC1 might define novel populations of human B cells with similarities to mouse B cells. We found that PC1 is expressed in small populations of human B lineage cells in peripheral blood, cord blood, tonsils, bone marrow and pediatric peritoneal fluid, with the highest levels in plasma cells. The characteristics of human PC1+ B cells differ from mouse peritoneal B‐1a subsets and from features of the human CD20+CD27+CD43+CD70− B‐cell subset proposed to be human B‐1 cells. Expression of PC1 was greatly increased in B cells stimulated with the combination of CD40 ligand, interleukin (IL)‐4 and IL‐21. In addition, PC1+ B cells activated CD4+ T regulatory cells. ENPP1 thus defines a subset of human B cells that differs significantly from mouse peritoneal B‐1a and proposed human B‐1 cells. [ABSTRACT FROM AUTHOR]