CD19 and B-cell chronic lymphocytic leukemia: Hence, the isolated CD3+CD4− lymphocytes expressed the same class I and class II alloantigens as did the CLL cells and differences in spot number between CD3+ T-lineage control stimulators and CD19+ B-lineage CLL stimulators represent specificity against CLL or at least against B-lineage antigens absent from the T-lineage antigenic repertoire.