CD22 and acute lymphoblastic leukemia: CD22RPF-specific T-cell clone 9D4 was isolated from a healthy HLA-B*07:02neg individual, efficiently produced cytokines upon stimulation with primary acute lymphoblastic leukemia and healthy B-cells, but did not react towards healthy hematopoietic and nonhematopoietic cell subsets, including dendritic cells (DCs) and macrophages expressing low levels of CD22.