CD169+ macrophages are sufficient for priming of CTLs with specificities left out by cross-priming dendritic cells.
Dendritic cells (DCs) are considered the most potent antigen-presenting cells (APCs), which directly prime or cross-prime MHC I-restricted cytotoxic T cells (CTLs). However, recent evidence suggests the existence of other, as-yet unidentified APCs also able to prime T cells. To identify those APCs, we used adenoviral (rAd) vectors, which do not infect DCs but selectively accumulate in CD169(+) macrophages (MPs). In mice that lack DCs, infection of CD169(+) MPs was sufficient to prime CTLs specific for all epitopes tested. In contrast, CTL responses relying exclusively on cross-presenting DCs were biased to selected strong MHC I-binding peptides only. When both DCs and MPs were absent, no CTL responses could be elicited. Therefore, CD169(+) MPs can be considered APCs that significantly contribute to CTL responses.
Institute for Immunology, Ludwig-Maximilian University of Munich, 80336 Munich, Germany and.
Caroline A
CA
Bernhard
Institute for Immunology, Ludwig-Maximilian University of Munich, 80336 Munich, Germany and.
Christine
C
Ried
Department of Gene Therapy, University of Ulm, 89081 Ulm, Germany.
Stefan
S
Kochanek
Institute for Immunology, Ludwig-Maximilian University of Munich, 80336 Munich, Germany and tbrocker@med.uni-muenchen.de.
Thomas
T
Brocker
D000818:Animals; D017951:Antigen Presentation / Q000502:physiology*; D015703:Antigens, CD / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D037181:Lectins, C-Type / Q000276:immunology*; D051379:Mice; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D037181:Lectins, C-Type; D000099192:CD69 Antigens
CD169+ macrophage; CD8 T cell; adenovirus; cross-presentation; dendritic cell