Blockade of the CD40-CD40 ligand pathway potentiates the capacity of donor-derived dendritic cell progenitors to induce long-term cardiac allograft survival.
BACKGROUND
Failure of costimulatory molecule-deficient donor dendritic cells (DCs) to induce indefinite allograft acceptance may be a result of the 'late" up-regulation of these molecules on the DCs after interaction with host T cells. Ligation of CD40 on antigen-presenting cells by its cognate ligand CD40L is thought to induce expression of CD80 (B7-1) and CD86 (B7-2). We examined the influence of anti-CD40L monoclonal antibody (mAb) on the capacity of donor-derived DC progenitors to induce long-term allograft survival.


METHODS
High purity DC progenitors were grown from B10 (H2b) mouse bone marrow in granulocyte-macrophage colony-stimulating factor and transforming growth factor beta1 (TGFbeta1). Mature DC were propagated in granulocyte-macrophage colony-stimulating factor and interleukin-4. Their phenotype was characterized by flow cytometric analysis and their function by mixed leukocyte reactivity. Anti-donor cytotoxic T lymphocyte activity in grafts and spleens of vascularized heart allograft recipients was also assessed.


RESULTS
The TGFbeta3-cultured cells were (1) DEC 205-positive, MHC class II-positive, CD80dim, CD86dim, and CD40dim, (2) poor stimulators of naive allogeneic T-cell proliferation, and (3) able to prolong significantly B10 cardiac allograft survival in C3H (H2k) recipients when given (2 x 10[6] i.v.) 7 days before organ transplantation (median survival time [MST] 26 days vs. 12 days in controls, and 5 days in interleukin-4 DC-treated animals). Their allostimulatory activity was further diminished by addition of anti-CD40L mAb at the start of the mixed leukocyte cultures. Anti-CD40L mAb alone (250 microg/mouse, i.p.; day -7) did not prolong cardiac graft survival (MST 12 days). In contrast, TGFbeta-cultured DCs + anti-CD40L mAb extended graft survival to a MST of 77 days, and inhibited substantially the anti-donor cytotoxic T lymphocyte activity of graft-infiltrating cells and host spleen cells assessed 8 days after transplant.


CONCLUSIONS
The CD40-CD40L pathway appears important in regulation of allogeneic DC-T-cell functional interaction in vivo; its blockade increases markedly the potential of costimulatory molecule-deficient DCs of donor origin to induce long-lasting allograft survival.
Lu
L
L
Thomas E. Starzl Transplantation Institute and Department of Surgery, University of Pittsburgh, Pennsylvania 15213, USA.
Li
W
W
Fu
F
F
Chambers
F G
FG
Qian
S
S
Fung
J J
JJ
Thomson
A W
AW
D000818:Animals; D000911:Antibodies, Monoclonal; D001854:Bone Marrow Cells / Q000276:immunology; D019013:CD40 Antigens / Q000276:immunology*; D023201:CD40 Ligand; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology; D006084:Graft Rejection / Q000276:immunology; D006085:Graft Survival; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D016027:Heart Transplantation / Q000276:immunology*; D016130:Immunophenotyping; D007165:Immunosuppression Therapy / Q000379:methods; D015847:Interleukin-4 / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D013997:Time Factors; D014019:Tissue Donors; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D019013:CD40 Antigens; D008562:Membrane Glycoproteins; D016212:Transforming Growth Factor beta; D023201:CD40 Ligand; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor