start stage end stage mature B cell naive B cell naive B-cell zebrafish_anatomy TAO:0009334 ZFA:0009334 naive B lymphocyte CL:0000788 A naive B cell is a mature B cell that has the phenotype surface IgD-positive, surface IgM-positive, CD27-negative, and CD38-negative, and that has not yet been activated by antigen in the periphery. naive B-lymphocyte unknown adult