Identification of a novel human B cell activation antigen involved in B cell growth factor-dependent proliferation

C. T.K. Tseng, C. F. Springgate, W. Tadmori, Y. S. Choi

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The B6.4 mAb we present here identifies a novel activation Ag of B cell lineage. The B6.4 mAb was generated by immunizing mice with B cell growth factor (BCGF)-responding BA3 cells, and selected by its capability to block BCGF-induced proliferation of BA3 cells. The inhibitory effect of this antibody on BCGF-dependent proliferation was further confirmed by using normal activated B cells in the presence of exogenous BCGF derived from T cells or B cells. Furthermore, it did not affect IL-2-dependent proliferation of B cells. The expression of the B6.4 Ag, as analyzed by FACS, is restricted to in vitro activated B cells, and remains undetectable on resting B or T cells, PHA-activated T cells, and monocytes. The B6.4 Ag is also expressed on some lymphoblastoid B cell lines and most of the lymphomas and CLL of B cell origin: however, it did not express on pre-B cell ALL and plasma cell leukemia. The B6.4 Ag has a M(r) of 35,000 Da, as determined by SDS-PAGE or radiolabeled immunoprecipitates from activated B cells. The B6.4 Ag is detectable on B cells as early as 8 h after activation, and precedes that of the IL-2R or transferrin R. All of these results suggest that the B6.4 Ag is an early activation Ag of B cells and is functionally related to a receptor of BCGF, but not IL-2.

Original languageEnglish (US)
Pages (from-to)2305-2311
Number of pages7
JournalJournal of Immunology
Issue number7
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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