pre-B cell morphology trait pre-B cell quantity The proportion or number of cells in the B lymphocyte lineage that have undergone VDJ rearrangement of the immunoglobulin heavy chain and are in the process of V-J rearrangement of the light chain: these cells express mu heavy chain on the cell surface. pre-B cell number number of pre-B cells pre-B lymphocyte cell number Trait.ontology VT:0008209 immature B cell quantity