Local accumulation and activation of regulatory Foxp3+ CD4 T(R) cells accompanies the appearance of activated CD8 T cells in the liver.
Only small populations of nonactivated, nonproliferating Foxp3(+) CD4 regulatory T cell (T(R)) cells are found in the nonparenchymal cell compartment of the mouse liver while liver-draining celiac nodes contain expanded, activated T(R) cell populations (similar to other lymph nodes). Liver Foxp3(+) CD4 T(R) cells suppress activation of T cell responses. Polyclonal, systemic T cell activation in vivo (via anti-CD3 antibody injection) is accompanied by intrahepatic accumulation of T blasts and a rapid but transient intrahepatic increase of activated, proliferating Foxp3(+) CD4 T(R) cells. Following vaccination, the appearance of peripherally primed, specific CD8 T blasts in the liver is preceded by a transient rise of Foxp3(+) CD4 T(R) cells in the liver. The adoptive transfer of immune CD8 T cells into congenic hosts that express the relevant antigen only in the liver leads to the accumulation of specific donor CD8 T cells and of host Foxp3(+) CD4 T(R) cells in the liver.


CONCLUSIONS
Although it contains only a small population of quiescent Foxp3(+) CD4 T(R) cells, the liver can rapidly mobilize and/or recruit this T cell control in response to the intrahepatic appearance of peripherally or locally generated CD8 T blasts.
Bochtler
Petra
P
Department of Internal Medicine I, University of Ulm, Ulm, Germany.
Riedl
Petra
P
Gomez
Ivan
I
Schirmbeck
Reinhold
R
Reimann
Jörg
J
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology*; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D008099:Liver / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal
D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse