CTLA-4 is not restricted to the lymphoid cell lineage and can function as a target molecule for apoptosis induction of leukemic cells

Maria Pia Pistillo, Pier Luigi Tazzari, Giulio Lelio Palmisano, Ivana Pierri, Andrea Bolognesi, Francesca Ferlito, Paolo Capanni, Letizia Polito, Marina Ratta, Stefano Pileri, Milena Piccioli, Giuseppe Basso, Laura Rissotto, Roberto Conte, Marco Gobbi, Fiorenzo Stirpe, Giovanni Battista Ferrara

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The expression of cytotoxic T-lymphocyte antigen-4 (CTLA-4) molecule in human normal and neoplastic hematopoietic cells, both on the cell membrane and in the intracellular compartment, was evaluated. Flow cytometric analysis carried out with a panel of anti-CTLA-4 human single-chain fragment of variable domain (scFv) antibodies revealed that CTLA-4 was not expressed on the surface, whereas it was highly expressed within the cytoplasm, in freshly isolated peripheral blood mononuclear cells (PBMCs), T cells, B cells, CD34+ stem cells, and granulocytes. Various treatments with agents able to specifically activate each cell type induced CTLA-4 expression on the surface of these cells. Similarly, increased CTLA-4 expression Was observed in different hematopoietic cell lines although they also expressed surface CTLA-4, at different degrees of intensity, before activation. Surprisingly, CTLA-4 RNA transcripts were detectable in such cell lines only after nested polymerase chain reaction (PCR) specific for CTLA-4 extracellular domain, suggesting a very fast CTLA-4 RNA processing accompanied by prolonged CTLA-4 protein accumulation. We further demonstrated surface expression of CTLA-4 in a variety of acute and chronic myeloid leukemias (AMLs and CMLs) and B- and T-lymphoid leukemias, either adult or pediatric. CTLA-4 was expressed in 25% to 85% of AMLs and CMLs depending on the leukemia subtype and the epitope analyzed, whereas in acute B-and T-leukemias CTLA-4 expression was mainly cytoplasmic. Chronic B leukemias appeared to express CTLA-4, both on the surface and in cytoplasm, whereas few cases tested of chronic T leukemias were negative. Two anti-CTLA-4 immunotoxins (scFvs-saporin) induced in vitro apoptosis of neoplastic cells from a representative AML, suggesting a novel immunotherapeutic approach to AM L based on CTLA-4 targeting.

Original languageEnglish
Pages (from-to)202-209
Number of pages8
Issue number1
Publication statusPublished - Jan 1 2003


ASJC Scopus subject areas

  • Hematology

Cite this

Pistillo, M. P., Tazzari, P. L., Palmisano, G. L., Pierri, I., Bolognesi, A., Ferlito, F., Capanni, P., Polito, L., Ratta, M., Pileri, S., Piccioli, M., Basso, G., Rissotto, L., Conte, R., Gobbi, M., Stirpe, F., & Ferrara, G. B. (2003). CTLA-4 is not restricted to the lymphoid cell lineage and can function as a target molecule for apoptosis induction of leukemic cells. Blood, 101(1), 202-209. https://doi.org/10.1182/blood-2002-06-1668