Autologous activated T cells that have been coated with bispecific antibodies (BiAb), with potential antineoplastic and immunomodulating activities. In vitro, T cells are activated through exposure to the anti-CD3 murine monoclonal antibody OKT3 and low-dose interleukin 2 (Il-2) for 6-14 days and then armed with anti-CD3 x anti-CD20 bispecific antibody (CD20Bi). Upon administration, anti-CD3 x anti-CD20 bispecific antibody-armed activated T cells (AATC) attach to CD3-expressing T cells and CD20-expressing tumor cells, selectively cross-linking T cells and tumor cells. This may result in the recruitment and activation of cytotoxic T lymphocyte (CTLs), CTL-mediated specific tumor cell lysis, and the secretion of antitumor cytokines and chemokines. CD20, a cell surface phosphoprotein, is found on normal B cells and most B-cell tumors.