CD4(+) T cells stimulate memory CD8(+) T cell expansion via acquired pMHC I complexes and costimulatory molecules, and IL-2 secretion.
The rapid and efficient expansion of CD8(+) memory T cells after the second encounter with a pathogen constitutes a hallmark trait of adaptive immunity. Yet, the contribution of CD4(+) T cells to the expansion of memory CD8(+) T cells remains the subject of controversy. Here, we show that, antigen-specific CD4(+) T cells, once activated by dendritic cells (DC) in vitro, have the capacity to stimulate expansion of memory CD8(+) T cells in vivo. The memory CD8(+) T cell expansion triggered by active CD4(+) T cells are mediated through DC-derived MHC I/peptide complexes and CD80 molecules displayed on the active CD4(+) T cells, with the involvement of IL-2 secreted by the active CD4(+) T cells. These results highlight a previously undescribed role of active CD4(+) T cells in triggering expansion of memory CD8(+) T cells.
Shi
Meiqing
M
Saskatchewan Cancer Agency, Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, 20 Campus Dr., Saskatoon S7N 4H4, Canada.
Hao
Siguo
S
Chan
Tim
T
Xiang
Jim
J
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells; D015395:Histocompatibility Antigens Class I / Q000276:immunology* / Q000378:metabolism; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D018345:Mice, Knockout; D010455:Peptides / Q000276:immunology / Q000378:metabolism
D015395:Histocompatibility Antigens Class I; D007376:Interleukin-2; D010455:Peptides