A B220-positive CD38-positive naive B cell is a CD38-positive naive B cell that has the phenotype B220-positive, CD38-positive, surface IgD-positive, surface IgM-positive, and CD27-negative, and that has not yet been activated by antigen in the periphery. [ GOC:dsd GOC:rhs GOC:tfm http://www.ncbi.nlm.nih.gov/pubmed/20123131 ]