In vivo trafficking and immunostimulatory potential of an intranasally-administered primary dendritic cell-based vaccine

Abstract

BackgroundCoccidioidomycosis or Valley fever is caused by a highly virulent fungal pathogen: Coccidioides posadasii or immitis. Vaccine development against Coccidioides is of contemporary interest because a large number of relapses and clinical failures are reported with antifungal agents. An efficient Th1 response engenders protection. Thus, we have focused on developing a dendritic cell (DC)-based vaccine for coccidioidomycosis. In this study, we investigated the immunostimulatory characteristics of an intranasal primary DC-vaccine in BALB/c mouse strain that is most susceptible to coccidioidomycosis. The DCs were transfected nonvirally with Coccidioides-Ag2/PRA-cDNA. Expression of DC-markers, Ag2/PRA and cytokines were studied by flow cytometry, dot-immunoblotting and cytometric bead array methods, respectively. The T cell activation was studied by assessing the upregulation of activation markers in a DC-T cell co-culture assay. For trafficking, the DCs were co-transfected with a plasmid DNA encoding HSV1 thymidine kinase (TK) and administered intranasally into syngeneic mice. The trafficking and homing of TK-expressing DCs were monitored with positron emission tomography (PET) using 18F-FIAU probe. Based on the PET-probe accumulation in vaccinated mice, selected tissues were studied for antigen-specific response and T cell phenotypes using ELISPOT and flow cytometry, respectively.ResultsWe found that the primary DCs transfected with Coccidioides-Ag2/PRA-cDNA were of immature immunophenotype, expressed Ag2/PRA and activated naïve T cells. In PET images and subsequent biodistribution, intranasally-administered DCs were found to migrate in blood, lung and thymus; lymphocytes showed generation of T effector memory cell population (TEM) and IFN-γ release.ConclusionsIn conclusion, our results demonstrate that the intranasally-administered primary DC vaccine is capable of inducing Ag2/PRA-specific T cell response. Unique approaches utilized in our study represent an attractive and novel means of producing and evaluating an autologous DC-based vaccine.

An agonist of human complement fragment C5a enhances vaccine immunity against Coccidioides infection

“…Earlier studies have reported that EP67 engaged the C5aR on the surface of human DC and facilitated presentation of T and B cell epitopes to which EP67 was conjugated [12,16]. Denditric cells have been suggested to be major contributors to the host protective response to Coccidioides infection by bridging between the innate and adaptive immune systems [43]. …”

Mechanisms of Dendritic Cell Trafficking Across the Blood–brain Barrier

“…The DCs were cotransfected with Coccidioides -Ag2/PRA-cDNA and a plasmid DNA encoding HSV1-TK. HSV1-TK phosphorylates 18 F-FIAU to phospho- 18 F-FIAU, which is then metabolically trapped and detected by the PET system (Vilekar et al 2010). As noted by this study, 111 In-oxine SPECT imaging for DC trafficking does not ensure the integrity of radiolabel and DC association in vivo, has poor resolution, and lastly allows imaging only up to 3 or 4 days.…”

Diphenyldifluoroketone EF24 Suppresses Pro-inflammatory Interleukin-1 receptor 1 and Toll-like Receptor 4 in lipopolysaccharide-stimulated dendritic cells

“…We used immortalized C57BL/6 mouse-derived JAWS II dendritic cells that show typical immunophenotype and morphology when cultured in presence of GM-CSF. The characteristics of these immortalized cells have been described in our previous reports [ 14 , 24 ].…”