has plasma membrane part naive B cell CD38-positive naive B cell CD38+ naive B-lymphocyte CD38-positive naive B-cell CD38+ naive B cell A CD38-positive naive B cell is a mature B cell that has the phenotype CD38-positive, surface IgD-positive, surface IgM-positive, and CD27-negative, and that has not yet been activated by antigen in the periphery. CD38+ naive B-cell CD38-positive naive B-lymphocyte CD38+ naive B lymphocyte CD38-positive naive B lymphocyte ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1