B220
Overview
B220 (CD45R; the RA isoform of CD45) is expressed on B lineage cells and is the equivalent of mouse B220. In humans, B220 expression is heterogeneous among B cell subsets: naive B cells universally express B220, while memory B cells can be divided into B220⁺ and B220⁻ fractions. Plasma cells downregulate B220.
Key Points from Literature
- Conventional CD27⁺ memory cells can be divided into B220⁺ and B220⁻ subsets; this heterogeneity is also found in DN B cells, confirming their similarity to conventional memory cells at this marker (see Wei2007 - DN Memory B Cells in SLE).
- Naive B cells universally express B220; memory cells (both CD27⁺ and DN) show partial downregulation (see Wei2007 - DN Memory B Cells in SLE, citing Bleesing & Fleisher 2003).
Contradictions & Debates
None documented in current wiki sources.
Related Pages
Double-Negative B Cell, Memory B Cell, CD27