A novel pathway of human B cell activation initiated by CK226 surface antigen

Alessandro Poggi, Enrico Maggi, Roberta Biagiotti, Maria Grazia Giudizi, Fabio Almerigogna, Nicoletta Pella, Federico Caligaris-Cappio, Sergio Romagnani, Lorenzo Moretta

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Abstract

In this study we analyzed the effect of CK226 monoclonal antibody (mAb) on human B cell activation and proliferation. This mAb was shown to recognize a 75-kDa surface molecule expressed on both T and B lymphocytes and to mediate T lymphocyte activation and proliferation. Flow cytometry analysis of B cell populations isolated from peripheral blood, tonsil and spleen showed that CK226 surface antigen is highly expressed on 40-80% of surface Ig+ cells. When purified B cells were cultured in the presence of CK226 mAb, up-regulation of major histocompatibility complex class II and CD23 surface structures and the de novo expression of CD25 antigen could be detected within 48 h. In addition, B cells underwent proliferation ([3H] thymidine uptake) in the absence of either Tcells or exogenous lymphokines. Proliferation was potentiated by the addition of suboptimal concentrations (0.5 ng/ml) of phorbol 12-myristate 13-acetate (PMA). Cells recovered at day 5 were surface Ig+ and no CD3+ cells could be detected. CK226-induced proliferation (either in the presence or in the absence of PMA) was not inhibited by anti-CD25 mAb. Addition of exogenous interleukin 2 to CK226-stimulated B cells resulted in further increase of B cell proliferation. On the other hand, CK226 mAb did not display a co-stimulatory effect with submitogenic concentrations of either anti-Ig antibody or Staphylococcus aureus Cowan strain I bacteria. In addition proliferation induced by mitogenic concentrations of the above stimuli was inhibited in a dose-dependent fashion by CK226 mAb.

Original languageEnglish
Pages (from-to)1161-1165
Number of pages5
JournalEuropean Journal of Immunology
Volume20
Issue number5
Publication statusPublished - May 1990

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ASJC Scopus subject areas

  • Immunology

Cite this

Poggi, A., Maggi, E., Biagiotti, R., Giudizi, M. G., Almerigogna, F., Pella, N., Caligaris-Cappio, F., Romagnani, S., & Moretta, L. (1990). A novel pathway of human B cell activation initiated by CK226 surface antigen. European Journal of Immunology, 20(5), 1161-1165.