183 Morphogenomic immune responsiveness to preventive/therapeutic vaccines

Abstract

We have previously reported that the transcriptional profile of VLPstimulated MDDCs shows the up-regulation of classic markers of MDDC activation. In particular, VLP-stimulation induced the activation of genes associated with antigen presentation and MDDCs migration. Subsequently, we have shown that a comparable transcriptional profiling can be obtained using PBMCs without further in vitro maturation in MDDCs. Fresh human peripheral blood mononuclear cells were isolated by Ficoll-Hypaque density gradient centrifugation and plated in 6-well plates at a concentration of 1 × 107/well. PBMCs were pulsed with 6 μg/mL of HIV-VLPs. After 16 hrs, the cells were harvested, washed, total RNA was isolated and RNA quality/quantity was estimated. Amplified antisense RNA (aRNA) was obtained from total RNA via two round of in vitro transcription. Testreference sample pairs were mixed and co-hybridized to a custom-made 37K oligo-based microarray platform encompassing the whole human genome. In the present study we show that VLPs induce ex vivo transcriptional activation comparable to that observed in in vitro matured MDDCs and the transcriptional patterns induced ex vivo by VLPs in PBMCs from normal donors equated the patterns observed ex vivo in unstimulated PBMC from HIV in patients. Moreover the baseline activation of immune genes observed in HIV-infected patients is further enhanced by ex vivo stimulation by VLPs resulting in a transcriptional activation superior to that observed in PBMC obtained from normal non HIV-infected volunteers. In summary, this study may provide a road map for the study of HIV-infected patients based on HIVspecific signatures, their heterogeneity among patients, their response to vaccine strategies. Future studies should take into account this findings for the discovery of potentially correlative patterns associated with the natural history of the disease and/or it response to treatment.