Adoptively transferred immunity persists in human marrow graft recipients

This study was designed to determine if antibodies (Abs) to recall antigens (Ags) were produced after bone marrow transplantation (BMT). Sera from marrow recipients (recipients) were tested for Abs to recall Ags post-grafting, and T and B cells from recipients were tested for their ability to produce anti-tetanus toxoid antibody (anti-TT) using in vitro biosynthesis assays. Neither the donors nor recipients received booster immunizations with recall Ags before or after BMT. Serum Ab titers to tetanus toxoid (TT), diphtheria toxoid (DT), and measles virus (MV) were in the normal range for the majority of 235 short-term recipients (less than 100 days postgrafting) and for the majority of 149 long-term (greater than 6 months postgrafting) recipients. Anti-TT was produced in vitro by peripheral blood lymphocytes (PBL) from 6 of 14 long-term recipients after TT stimulation. In another system, purified B cells from 9 of 21 long-term recipients also produced anti-TT after Epstein-Barr virus (EBV) stimulation. The presence of Ab titers to TT, DT, and MV in the serum of recipients and the production of in vitro anti-TT by T and B cells from recipients show that Ag-specific memory was transferred via the marrow inoculum. These data show that adoptively transferred immunity persists in recipients for years postgrafting.