• Antibody-based targeting and monoclonal antibodies (mAbs) became central to cancer therapy, enabling predefined specificity, targeted cytotoxicity, and antibody–toxin strategies across leukemias/lymphomas. Evidence includes continuous cultures with predefined specificity, serotherapy, and antibody conjugates [1], [2], [3], [6], [10], [13], [16], [18], [20].

• Humoral components reveal paradoxical tumor-immune modulation, with sera blocking lymphocyte-mediated tumor rejection, serum factors protecting neoplastic cells, and antigen–antibody complexes influencing recognition [5], [12], [14], [15].

• T-cell biology and subset targeting via monoclonal antibodies advanced immune regulation research, revealing Ly antigen-defined T-cell classes, separable functional subsets, and cytotoxic/suppressor lineages with TH2 associations [6], [9], [13], [18].

• Combined chemoimmunotherapy and transplantation strategies extended remission in hematologic malignancies, illustrating integration of immune targeting with conventional therapies like chemotherapy and allogeneic marrow transplantation [3], [8], [19].

• Antibody–toxin conjugates achieved targeted cytotoxicity, exemplified by ricin A chain conjugates and related toxin-delivery approaches against antigen-bearing cells [16], [20].