Targeting of T lymphocytes against EGF-receptor+ tumor cells by bispecific monoclonal antibodies: Requirement of CD3 molecule cross-linking for T-cell activation

S. Ferrini, A. Cambiaggi, S. Sforzini, S. Marciano, S. Canevari, D. Mezzanzanica, M. I. Colnaghi, C. E. Grossi, L. Moretta

Research output: Contribution to journalArticlepeer-review

Abstract

Targeting of T lymphocytes against epidermal growth-factor receptor (EGF-R)+ tumor cells was achieved by constructing a hybrid hybridoma which secretes an anti-EGF-R/anti-CD3 bispecific monoclonal antibody (biMAb) of hybrid isotype (IgG1/IgG(2a)). Purification of biMAb molecules from parental anti-EGF-R and anti-CD3 MAbs was performed by protein-A chromatography. The purified biMAb was able to trigger the lysis of EGF-R+ tumor cell lines (A431, IGROV-I, MDA-468 and U-87) and of NIH-3T3 transfectants expressing human EGF-R by cytolytic T lymphocytes, but it was ineffective in the case of EGF-R-negative tumor targets. Mormal EGF-R+ cells (keratinocytes and endometrial cells) were also susceptible to biMAb-targeted cytolysis. However, the amount of biMAb required to induce half-maximal cytolysis of tumor cells over-expressing the EGF-R molecule (A431) was considerably lower than that required to induce lysis of EGF-R+ tumor or normal cells which express EGF-R at considerably lower density. The ability of such biMAbs to deliver activation signals to T cells was evaluated by Ca++ mobilization and lymphokine production experiments. The soluble anti-EGF-R/anti-CD3 biMAb failed to induce intracellular Ca++ increases, which occurred only after cross-linking induced by an anti-mouse IgG antibody. Secretion of lymphokines (IFN-γ, TNF-α and GM-CSF) was induced by contact of the biMAb-coated effector cells with the relevant tumor target, whereas the soluble biMAb was virtually ineffective. In addition, biMAb-coated effector cells retained the ability to recognize and to lyse EGF-R+ tumor cells for a prolonged period of time. Our data indicate that activation of effector cells targeted by biMAbs can only occur at the tumor site, where cross-linking of surface CD3 molecules is induced by contact with the tumor cells.

Original languageEnglish
Pages (from-to)931-937
Number of pages7
JournalInternational Journal of Cancer
Volume55
Issue number6
DOIs
Publication statusPublished - 1993

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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