In vitro sensitization of T cells with DC-associated/delivered HIV constructs can induce a polyfunctional CTL response, memory T-cell response, and virus suppression

Human dendritic cell targeting peptide can be targeted to porcine dendritic cells to improve antigen capture efficiency to stimulate stronger immune response

Dendritic cells (DCs) play a key role in the natural recognition of pathogens and subsequent activation of adaptive immune responses due to their potent antigen-presenting ability. Dendritic cell-targeting peptide (DCpep) is strongly targeted to DCs, which often express antigens, to enhance the efficacy of vaccines. Our previous study showed that recombinant Lactobacillus expressing human DCpep could significantly induce stronger immune responses than recombinant Lactobacillus without DCpep, but the mechanism remains unclear. In this study, the mechanism by which DCpep enhances the immune response against recombinant Lactobacillus was explored. Fluorescence-labeled human DCpep was synthesized to evaluate the binding ability of human DCpep to porcine monocyte-derived dendritic cells (Mo-DCs) and DCs of the small intestine. The effects of Mo-DC function induced by recombinant Lactobacillus expressing human DCpep fused with the porcine epidemic diarrhea virus (PEDV) core neutralizing epitope (COE) antigen were also investigated. The results showed that human DCpep bind to porcine DCs, but not to porcine small intestinal epithelial cells. Human DCpep can also improve the capture efficiency of recombinant Lactobacillus by Mo-DCs, promote the maturation of dendritic cells, secrete more cytokines, and enhance the ability of porcine DCs to activate T-cell proliferation. Taken together, these results promote advanced understanding of the mechanism by which DCpep enhances immune responses. We found that some DCpeps are conserved between humans and pigs, which provides a theoretical basis for the development of a DC-targeted vaccine.

Therapeutic Vaccination With Dendritic Cells Loaded With Autologous HIV Type 1-Infected Apoptotic Cells

BACKGROUND

We report the results of a phase I/II, open-label, single-arm clinical trial to evaluate the safety and anti-human immunodeficiency virus type 1 (HIV-1) efficacy of an autologous dendritic cell (DC)-based HIV-1 vaccine loaded with autologous HIV-1-infected apoptotic cells.

METHODS

Antiretroviral therapy (ART)-naive individuals were enrolled, and viremia was suppressed by ART prior to delivery of 4 doses of DC-based vaccine. Participants underwent treatment interruption 6 weeks after the third vaccine dose. The plasma HIV-1 RNA level 12 weeks after treatment interruption was compared to the pre-ART (ie, baseline) level.

RESULTS

The vaccine was safe and well tolerated but did not prevent viral rebound during treatment interruption. Vaccination resulted in a modest but significant decrease in plasma viremia from the baseline level (from 4.53 log10 copies/mL to 4.27 log10 copies/mL;P= .05). Four of 10 participants had a >0.70 log10 increase in the HIV-1 RNA load in plasma following vaccination, despite continuous ART. Single-molecule sequencing of HIV-1 RNA in plasma before and after vaccination revealed increases in G>A hypermutants in gag and pol after vaccination, which suggests cytolysis of infected cells.

CONCLUSIONS

A therapeutic HIV-1 vaccine based on DCs loaded with apoptotic bodies was safe and induced T-cell activation and cytolysis, including HIV-1-infected cells, in a subset of study participants.

CLINICAL TRIALS REGISTRATION

NCT00510497.

Effects of porcine epidemic diarrhea virus on porcine monocyte-derived dendritic cells and intestinal dendritic cells

Infection with porcine epidemic diarrhea virus (PEDV) causes damage to intestinal epithelial cells and results in acute diarrhea and dehydration with high mortality rates in swine. Dendritic cells (DCs) are highly effective antigen-presenting cells widely distributed beneath the intestinal epithelium, thus making them an early target for virus contact. DCs uptake and present viral antigens to T cells, which then initiate a distinct immune response. In this study, we investigated how attenuated PEDV (CV777) affects the function of porcine monocyte-derived dendritic cells (Mo-DCs). Our results show that the expression of Mo-DC surface markers such as SWC3a(+)CD1a(+), SWC3a(+)CD80/86(+) and SWC3a(+)SLA-II-DR(+) is increased after infection with CV777 for 24 h. Mo-DCs infected with CV777 produce higher levels of IL-12 and INF-γ compared to mock-infected Mo-DCs but the expression profile for IL-10 does not change. Interactions between Mo-DCs and CV777 significantly influence the stimulation of the T cell response in vitro. Consistent with these results, after 48 h of CV777 infection, there is enhancement in the ability of porcine intestinal DCs to sample the antigen and activate T-cell proliferation in vivo. The enhancement of sampling and presentation is most pronounced for immature Mo-DCs. These results suggest that CV777 stimulates the ability of Mo-DCs to sample and present antigen. We conclude that CV777 may be a useful vaccine to trigger adaptive immunity.