Lumenal part of the DC-LAMP protein is not required for induction of antigen-specific T cell responses by means of antigen-DC-LAMP messenger RNA-electroporated dendritic cells.
Previous studies showed that stimulation of T cells derived from HIV-1-infected patients with autologous dendritic cells electroporated with mRNA encoding HIV antigens can induce antigen-specific T cell responses in vitro. Linking the antigen to an MHC class II-targeting sequence, such as dendritic cell lysosome-associated membrane protein (DC-LAMP), in the mRNA construct results in presentation of antigenic peptides in both MHC class I and class II molecules and therefore enhances the induced T cell responses. To analyze whether the lumenal domain of DC-LAMP is required for optimal induction of cellular immunity against HIV antigens, we compared fusion constructs with or without the lumenal domain of the DC-LAMP protein. A human codon-optimized consensus Gag sequence and a chimeric cDNA sequence encompassing Tat, Rev, and Nef codons (TaReNef ) were cloned into a vector containing the DC-LAMP sequence with or without its lumenal domain. The Gag protein lacking the DC-LAMP-derived sequence altogether elicited only weak T cell responses. DCs electroporated with Gag or TaReNef linked to DC-LAMP were able to elicit similar levels of antigen-specific CD4(+) and CD8(+) T cell responses for both Gag and TaReNef, irrespective of the addition of the DC-LAMP lumenal domain. These data show that DC-LAMP-mediated antigen targeting is absolutely required for optimal T cell stimulation, but that in our experimental setup, the lumenal part of DC-LAMP does not improve the overall induction of antigen-specific T cell responses.
De Keersmaecker
Brenda
B
Laboratory of Molecular and Cellular Therapy, Vrije Universiteit Brussel, 1090 Brussels, Belgium.
Heirman
Carlo
C
Allard
Sabine
S
Bonehill
Aude
A
Corthals
Jurgen
J
Thielemans
Kris
K
Aerts
Joeri L
JL
D017951:Antigen Presentation; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D018274:Electroporation; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015658:HIV Infections / Q000276:immunology / Q000821:virology; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D051907:Lysosomal Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology*
D015683:Gene Products, gag; D051907:Lysosomal Membrane Proteins; D012333:RNA, Messenger