Human donor bone marrow cells induce in vitro "suppressor T cells" that functionally suppress autologous B cells.
We have reported a beneficial effect of donor vertebral body bone marrow cells (DBMC) infusions in cadaver renal allograft recipients in a 6-year follow-up, but with a transient increase in early (6 month) postoperative CMV infections and concomitant suppressed immunoglobulins (Ig) production. We also found that although there was no difference between the DBMC-infused and non-infused (control) groups in the development of donor-specific antibody, we now describe an additional difference seen in the percent reactive antibody (PRA) reactivity against a panel of HLA antigens that developed postoperatively. We hypothesize that (allogeneic) antigen presenting cells in the DBMC, systemically infused, caused the generation of recipient T suppressor (T4-suppressor) cells, thereby "inducing" a negative influence on B cell Ig production. We tested this notion in vitro by incubating PBL from CMV IgG positive laboratory volunteers with either (allogeneic) T-cell depleted DBMC or donor spleen cells (DSPC) from (the same) cadaver donors. After 7 days, the (responding) T cells were collected using magnetic beads and placed in culture with purified B cells freshly obtained from the same (autologous) CMV positive volunteer. To these cultures were added either media or 40 ng of CMV antigen. After 3, 5, 7, and 9 days, the expression of surface anti-CMV Ig was measured by flow cytometry using a panel of fluorescent markers double-labeled for activated B cells (CD20, CD19, and HLA DRw) and CMV-FITC. We also determined the phenotype of the cultured T cells using anti-CD3, CD4, and CD62L specific monoclonal antibodies. B cells that had been in contact with autologous T cells derived from DBMC cultures (TBM) were less likely to express anti-CMV surface Ig than those cultured with DSPC (TSP). The flow cytometry analysis revealed an increase in the number of T4 suppressor cells (CD3+, CD4+, CD62L+) in the TBM group, whereas the T4 helper phenotype (CD3+, CD4+, CD62L-) predominated in the TSP group. These in vitro findings support the notion that (allogeneic) DBMC infusions can induce a T4 suppressor (regulatory) influence and thereby indirectly affect B-cell function.
Carreno
Manuel R
MR
Departments of Surgery, Division of Transplantation, University of Miami School of Medicine, Miami, FL 33101, USA. mcarreno@med.miami.edu
Fuller
Laphalle
L
Mathew
James M
JM
Ciancio
Gaetano
G
Burke
George W
GW
Esquenazi
Violet
V
Ricordi
Camillo
C
Tzakis
Andreas G
AG
Miller
Joshua
J
D001853:Bone Marrow / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology*; D018929:Cell Culture Techniques; D006801:Humans; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D023001:Transplantation Tolerance / Q000276:immunology; D014184:Transplantation, Homologous