摘要：

The translocated oncogene in (BL) and () has been proposed to be expressed at a stage of differentiation at which the gene is normally silent, resulting in a continuous proliferation and an inhibited terminal differentiation. To determine whether is differently expressed at the various stages of the differentiation pathway, we used B-type (B-CLL) , representing resting B lymphocytes, inducible to proliferation and/or differentiation in vitro. The , and Ig lambda-light chain and PCA-1 antigen as markers of B-, were analyzed in single, morphologically defined by immunocytochemical double-staining. The proliferation of individual was determined by 3H-incorporation and by analysis of Ki-67 antigen expression. The results show that the level of expression correlates to the stage of differentiation and to the proliferative activity. Uninduced resting did not express . The was observed in the highest amount at the proliferative B-lymphoblast stage of maturation and was reduced in plasmablasts and undetectable in plasma . The results suggest that maturation of B into nonproliferative, terminally differentiated plasma is associated with a downregulated expression and thus support the view that the deregulated gene in BL and is expressed at an inappropriate stage of maturation and thereby inhibits terminal differentiation.

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