Table 1.

Observations implicating roles for donor-derived or recipient immune cells in mouse liver transplant tolerance

Cells or Molecules	Findings regarding transplant tolerance	Reference
Donor-derived Cells
Dendritic cells	Systemic donor-derived hematopoietic cell chimerism in liver transplant host lymphoid tissues	Qian S, Hepatology, 19949
	Propagation of donor DC from lymphoid tissue of liver transplant but not heart transplant recipients	Lu L, J Exp Med, 199515
	Proposed immunological role of donor-derived DC in bone marrow chimerism in host	Thomson AW, Transplantation, 199516
	Marked increases in DC within the graft induces rejection that can be reversed with IL- 12 blockade.	Li W, J Immunol 200122
	DAP12 expression by liver dendritic cells may be critical for the induction of tolerance	Yoshida O, Am J Transplant, 201424
Kupffer cells	Kupffer cells are not critical for tolerance	Morita M, Hepatology, 201525
NKT cells	NKT cells play a key immunomodulatory role	Morita M, Transpl Immunol, 200726
	Donor NK and NKT cells remain in liver and blood and are resistant to rejection	Tay SS, Liver Transplant, 201314
Hepatic stellate cells	Upregulated PD-L1 expression by stellate cells is important in tolerance induction	Morita M, Hepatology, 201525
Host cells
Cytotoxic T cells	Apoptosis of cytotoxic T lymphocytes within the grafts may provide a mechanistic basis of allograft acceptance.	Qian S, J Immunol 199729
Regulatory T cells	Depletion of host regulatory T cells increases alloimmune responses	Jiang X, Liver Transplant, 200631 Li W, Am J Transplant, 200832

In addition, expression of Fas (CD95) and FasL by various immune cells (and hepatocytes) may play an important role in regulation of anti-donor CTL responses.¹¹