Recall and propagation of allospecific memory T cells independent of secondary lymphoid organs.
The allospecifc T cell population responding to a transplanted organ consists of both naive and memory lymphocytes. Although it is established that naive T cells are activated by antigen within the organized structures of secondary lymphoid organs (the spleen, lymph nodes, and mucosal lymphoid tissues), it is not clear whether memory T cell activation and propagation depend on homing to these organs. To answer this question, we investigated whether allospecific naive or memory T cells can mediate acute cardiac allograft rejection in mutant mice that lack all of their secondary lymphoid tissues. The results of our experiments demonstrated that antigen-experienced memory T cells have two advantages over naive T cells: (i) memory T cells mount a vigorous immune response that leads to allograft rejection independent of secondary lymphoid organs; and (ii) memory T cells generate more memory T cells without homing to secondary lymphoid organs. These unique properties of memory T cells were further confirmed by showing that memory-like T cells that arise from the homeostatic proliferation of naive T cells in the absence of antigenic stimulation are suboptimal at rejecting allografts and do not generate memory T cells in mice devoid of secondary lymphoid tissues.
Chalasani
Geetha
G
Section of Nephrology (Department of Medicine) and Section of Immunobiology, Yale University School of Medicine, P.O. Box 208029, 333 Cedar Street, New Haven, CT 06520, USA.
Dai
Zhenhua
Z
Konieczny
Bogumila T
BT
Baddoura
Fady K
FK
Lakkis
Fadi G
FG
D000818:Animals; D017690:Cell Transplantation; D005434:Flow Cytometry; D007156:Immunologic Memory; D016130:Immunophenotyping; D008198:Lymph Nodes / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009092:Mucous Membrane / Q000276:immunology*; D009154:Mutation; D011995:Recombination, Genetic; D013154:Spleen / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism