Recombinant adeno-associated virus vectors induce functionally impaired transgene product–specific CD8+ T cells in mice
Shih-Wen Lin, … , Marcio O. Lasaro, Hildegund C.J. Ertl
Shih-Wen Lin, … , Marcio O. Lasaro, Hildegund C.J. Ertl
Published November 15, 2007
Citation Information: J Clin Invest. 2007;117(12):3958-3970. https://doi.org/10.1172/JCI33138.
View: Text | PDF
Research Article

Recombinant adeno-associated virus vectors induce functionally impaired transgene product–specific CD8+ T cells in mice

Abstract

Recombinant adeno-associated virus (rAAV) vectors were used in human trials as carriers of vaccines for HIV-1 after encouraging preclinical results. However, the clinical trials yielded disappointing results. Here we demonstrated that in mice, rAAV vectors expressing the gene encoding HIV-1 gag stimulated gag-specific CD8+ T cells, but these T cells failed to expand after a booster immunization with a replication-defective adenoviral (Ad) vector also expressing gag. We tested rAAV vectors of different serotypes expressing HIV-1 gag for induction of transgene product–specific CD8+ T cells and found that the immunoinhibitory effect of rAAV priming observed with different AAV serotypes was transgene product specific, was independent of the interval between prime and boost, and extended to boosts with vaccine modalities other than Ad vectors. rAAV vector–induced CD8+ T cells proliferated poorly, produced low levels of IFN-γ in response to gag stimulation, and upregulated immunoinhibitory molecules. These T cells did not protect efficiently against challenge with a surrogate pathogen. Finally, we showed that the impaired proliferative capacity of the T cells was caused by persistence of the antigen-encoding rAAV vectors and could be reversed by placing the CD8+ T cells in an antigen-free environment. Our data suggest that rAAV vectors induce functionally impaired T cells and could dampen the immune response to a natural infection.

Authors

Shih-Wen Lin, Scott E. Hensley, Nia Tatsis, Marcio O. Lasaro, Hildegund C.J. Ertl

×

Figure 2

Transgene product–specific CD8+ T cells fail to expand in response to a booster immunization.

Options: View larger image (or click on image) Download as PowerPoint
Transgene product–specific CD8+ T cells fail to expand in response to a ...
(A) BALB/c mice were primed i.m. with 1011 gc AAV2/7gag, and then 1 month later boosted i.m. with 1010 vp AdC68gag. Control mice were immunized with only the rAAV vaccine or only the AdC68 vaccine. (B and C) At 10 days (B) and 2 months (C) after the AdC68 immunization, splenocytes were stained with an antibody to CD8 and a gag-specific tet. Splenocytes were also stimulated with the AMQMLKETI peptide and analyzed by ICS for frequencies of gag-specific IFN-γ– and TNF-α–producing CD8+ T cells. (D and E) The order of immunizations was switched (D), and gag-tet–specific CD8+ T cell frequencies were determined by flow cytometry (E). Background frequencies (less than 0.1%) were subtracted prior to plotting. Frequencies shown are representative of at least 3 independent experiments. Error bars represent SD for 5 mice per group.