Antitumor effect of donor marrow graft rejection induced by recipient leukocyte infusions in mixed chimeras prepared with nonmyeloablative conditioning: critical role for recipient-derived XXXX .

@entity1 @entity19 @entity5 @entity786 @entity2800 @entity2132 @entity379 @entity1583 @entity43423
Some @entity1 lose chimerism following nonmyeloablative hematopoietic cell transplantation (HCT), yet, surprisingly, enjoy sustained @entity5 remissions. We hypothesized that host-versus-graft (HVG) alloresponses might induce antitumor effects against @entity5 . We explored this question in @entity19 by administering recipient leukocyte infusions (RLIs) to mixed chimeras established with nonmyeloablative conditioning. Mixed chimeras were prepared in the B10.A (H2a)-->B6 (H2b) strain combination using depleting anti-T-cell monoclonal antibodies (mAbs), @entity786 , and thymic irradiation. B6 @entity2800 cells (MMB3.19) were administered 7 days following donor lymphocyte infusion (DLI) or @entity43423 on day 35. Conversion to full donor chimerism occurred without @entity2132 ( @entity2132 ) following DLI, whereas @entity43423 led to loss of chimerism. Both @entity43423 and DLI significantly delayed @entity5 mortality. In another strain combination (B10.BR [H2k]-->BALB/c [H2d]), @entity43423 -induced or spontaneous loss of chimerism was associated with antitumor effects against the host-type B-cell lymphoma A20. HCT was essential for the antitumor effect of @entity43423 . @entity43423 induced elevated serum @entity379 ( @entity379 ) levels, and recipient-derived @entity379 was critical for their antitumor effects. Thus, HVG reactions (spontaneous or induced by @entity43423 ) mediate antitumor effects against @entity1583 via a recipient-derived @entity379 -mediated mechanism. A novel approach to achieving anti- @entity5 effects without the risk of @entity2132 is suggested.
