ZAP-70 is expressed by normal and malignant human B-cell subsets of different maturational stage

C. Scielzo, A. Camporeale, M. Geuna, M. Alessio, A. Poggi, M. R. Zocchi, M. Chilosi, F. Caligaris-Cappio, Paolo Ghia

Research output: Contribution to journalArticlepeer-review


ZAP-70 tyrosine kinase is involved in signalling pathways following T-cell receptor stimulation and was originally described only in T cells and natural killer cells. ZAP-70 expression has been reported in normal mouse B lineage cells and in human malignant B lymphocytes, mainly in chronic lymphocytic leukemia (CLL) where it correlates with clinical outcome. We analyzed several B-cell lines and ex vivo malignant B cells, ranging from acute lymphoblastic leukemia to multiple myeloma and reflecting different stages of B-cell differentiation, and they showed ZAP-70 expression regardless their maturation stage. We then analyzed by Western blot and flow cytometry different human normal B-lymphocyte subpopulations: naïve, germinal center and memory B cells from tonsils, CD19+ CD5+ cells from cord blood and CD19+ lymphocytes from peripheral blood. All expressed ZAP-70 protein, though at different levels depending on their differentiation, activation and tissue localization. In addition, ZAP-70 expression levels could be modulated following stimulation via the B-cell receptor. These findings implicate a potential role of ZAP-70 in the signalling pathway of B lymphocytes at different maturational stages, indicate that ZAP-70 expression is not a CLL-specific feature among B-cell malignancies and suggest that the absence of ZAP-70 rather than its presence should be considered abnormal for malignant B lymphocytes.

Original languageEnglish
Pages (from-to)689-695
Number of pages7
Issue number4
Publication statusPublished - Apr 2006


  • B lymphocytes
  • B-lymphoid malignancies
  • Chronic lymphocytic leukemia
  • ZAP-70

ASJC Scopus subject areas

  • Hematology
  • Cancer Research


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