title: Adoptive transfer of tumor reactive B cells confers host T-cell immunity and tumor regression.
abstract: OBJECTIVE
  We investigated the antitumor reactivity of adoptively transferred effector B cells and the mechanisms by which they may mediate tumor regression in a spontaneous metastases model.
  
  
  METHODS
  4T1 breast cancer cells were inoculated into the flanks of syngeneic Balb/C mice to prime draining lymph nodes. Tumor-draining lymph nodes (TDLN) were harvested and B cells activated ex vivo with lipopolysaccharide and anti-CD40 monoclonal antibody. These activated B cells were adoptively transferred into mice inoculated with 4T1 tumor in the mammary fat pad. The induction of host T-cell immunity was evaluated.
  
  
  RESULTS
  Activated 4T1 TDLN B cells secreted immunoglobulin G (IgG) in response to tumor cells which was immunologically specific. These activated B cells were capable of mediating specific lysis of tumor cells in vitro. Transfer of these activated B cells alone mediated the inhibition of spontaneous metastases to the lung. Examination of the host revealed that the transfer of these B cells resulted in the induction of tumor-specific T-cell immunity as measured by cytotoxicity and cytokine (IFNγ and granulocyte-macrophage colony-stimulating factor) production. The combined transfer of activated T and B cells from TDLN resulted in tumor regression, which was greater than either cell population alone, with host B cells capable of producing IgG that mediated lysis of tumor in the presence of complement.
  
  
  CONCLUSIONS
  We have found that appropriately primed B cells can mediate tumor regression by itself and confers host T-cell antitumor immunity. Furthermore, effector B cells can serve as a useful adjunct in adoptive T-cell therapy.
authors.affiliation: Division of Surgical Oncology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Li
authors.forename: Xiangming
authors.initials: X
authors.lastname: Lao
authors.forename: Qin
authors.initials: Q
authors.lastname: Pan
authors.forename: Ning
authors.initials: N
authors.lastname: Ning
authors.forename: Ji
authors.initials: J
authors.lastname: Yet
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Xu
authors.forename: Shengping
authors.initials: S
authors.lastname: Li
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Chang
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D008175:Lung Neoplasms / Q000517:prevention & control* / Q000556:secondary* / Q000628:therapy; D008213:Lymphocyte Activation; D008325:Mammary Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D013601:T-Lymphocytes / Q000276:immunology*