DEC-205 receptor on dendritic cells mediates presentation of HIV gag protein to CD8+ T cells in a spectrum of human MHC I haplotypes

L Bozzacco, C Trumpfheller… - Proceedings of the …, 2007 - National Acad Sciences
L Bozzacco, C Trumpfheller, FP Siegal, S Mehandru, M Markowitz, M Carrington…
Proceedings of the National Academy of Sciences, 2007National Acad Sciences
Optimal HIV vaccines should elicit CD8+ T cells specific for HIV proteins presented on MHC
class I products, because these T cells contribute to host resistance to viruses. We had
previously found that the targeting of antigen to dendritic cells (DCs) in mice efficiently
induces CD8+ T cell responses. To extend this finding to humans, we introduced the HIV
p24 gag protein into a mAb that targets DEC-205/CD205, an endocytic receptor of DCs. We
then assessed cross-presentation, which is the processing of nonreplicating internalized …
Optimal HIV vaccines should elicit CD8+ T cells specific for HIV proteins presented on MHC class I products, because these T cells contribute to host resistance to viruses. We had previously found that the targeting of antigen to dendritic cells (DCs) in mice efficiently induces CD8+ T cell responses. To extend this finding to humans, we introduced the HIV p24 gag protein into a mAb that targets DEC-205/CD205, an endocytic receptor of DCs. We then assessed cross-presentation, which is the processing of nonreplicating internalized antigen onto MHC class I for recognition by CD8+ T cells. Low doses of αDEC-gag, but not control Ig-gag, stimulated proliferation and IFN-γ production by CD8+ T cells isolated from the blood of HIV-infected donors. αCD205 fusion mAb was more effective for cross-presentation than αCD209/DC-SIGN, another abundant DC uptake receptor. Presentation was diverse, because we identified eight different gag peptides that were recognized via DEC-205 in 11 individuals studied consecutively. Our results, based on humans with highly polymorphic MHC products, reveal that DCs and DEC-205 can cross-present several different peptides from a single protein. Because of the consistency in eliciting CD8+ T cell responses, these data support the testing of αDEC-205 fusion mAb as a protein-based vaccine.
National Acad Sciences