Primary human immune response to dendritic cell inoculation in humanized mice

Models for investigating the use of human dendritic cells (DC) in active immunotherapy are limited. Humanized (Hu) NOD/SCID mice were evaluated for their capacity to respond to injected allogenic DCs. Hu-mice were generated by implanting human fetal thymus and liver under the kidney capsule, followed 3 weeks later by injection of autologous CD34+ cells. Flow cytometry analysis for human cells in peripheral blood of n=11 mice at 4 months showed: 59+13% CD45+ cells, 83+2% T cells, 9% B cells, and 2% myeloid cells. Human cells were present in bone marrow, 16+7%, spleen, 30+6%, and lymph nodes 2+0.4%. T and B cells were organized in germinal centre-like structures in the spleen. Mice were inoculated intravenously with luciferase gene marked human, allogenic DCs to localize migration patterns and evaluate immune responses. Bioluminescence imaging showed DCs throughout mice and in organs. Stimulation of spleen cells from DC inoculated mice, in vitro, with matched autologous or allogenic DCs, showed proliferation of CD8+ T cells to only the Hu-mouse allogenic cells used for injection. CD8+ T cells expressed the perforin degranulation marker, CD107a, and half of these cells were positive for intracellular IFNr, indicating acquired cytotoxic function. Studies are underway to assess responses to CMV antigens. Hu-mice may be useful for investigating primary immune responses to vaccines. Supported by DARPA W81XWH-04-C0139