title: Dendritic cell-T cell interactions: CD8 alpha alpha expressed on dendritic cells regulates T cell proliferation.
abstract: Expression of the CD8 alpha alpha homodimer has been used to differentiate lymphoid (CD8alpha(+)) from myeloid (CD8alpha(-)) dendritic cells (DCs). We have reported that CD8alpha(+) and CD8alpha(-) DCs have differential abilities to stimulate proliferation in allogeneic T cells. However, no specific function has been attributed to DC-derived CD8alpha. The current study examines the hypothesis that CD8 alpha alpha expression on DCs regulates DC-induced T cell activation. CD8alpha(-) transduced bone marrow-derived DCs were more potent stimulators of T cell proliferation, and produced significantly greater quantities of IL-12 in co-culture with T cells. LCK, a kinase whose expression is reported to be T cell-restricted and known to bind to the cytoplasmic tail of CD8 alpha beta in T cells, was detected readily in primary CD8alpha(+) splenic DCs and at greater levels than CD8alpha(-) DCs from the same tissues. LCK also co-precipitated with CD8alpha on immunblots strongly suggesting its role in CD8alpha(+) DC-induced T cell activation. Collectively, these data show that CD8alpha expressed on DC may not only be a lineage/maturation marker but also contribute to DC function.
authors.affiliation: Center for Immunobiology, Indiana University School of Medicine, Indianapolis, IN 46202-5120, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Hong
authors.forename: Tonya J
authors.initials: TJ
authors.lastname: Webb
authors.forename: David S
authors.initials: DS
authors.lastname: Wilkes
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D049109:Cell Proliferation; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D018664:Interleukin-12 / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain; C431698:CD8alpha antigen; D018664:Interleukin-12; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)