Project description:Rhesus macaques (RMs) inoculated with live-attenuated Rev-Independent Nef¯ simian immunodeficiency virus (Rev-Ind Nef¯SIV) as adults or neonates controlled viremia to undetectable levels and showed no signs of immunodeficiency over 6-8 years of follow-up. We tested the capacity of this live-attenuated virus to protect RMs against pathogenic, heterologous SIVsmE660 challenges Blood PBMC Time after SIV infection: 2 weeks post SIV infection Infection:Rev-Ind Nef¯SIV
Project description:Enteric fever is a major public health problem and causes numerous deaths annually. Ty21a is the only efficacious oral, live attenuated typhoid vaccine currently licensed for use, however, its mechanism of protection is poorly understood. To address this knowledge gap, we interrogated transcriptional profiles following vaccination with Ty21a and an immunogenic experimental oral live attenuated vaccine, M01ZH09, and related these findings to immunogenicity, and incubation period and disease severity following challenge with Salmonella Typhi four weeks after vaccination. Despite originating from the same parent strain (Ty2), we detected marked differences in the gene expression between both vaccines. Analysis of the transcriptome 7 days after M01ZH09 vaccination implicated transcriptional patterns associated with the cell cycle correlated significantly with humoral immunogenicity 28 days after vaccination. In contrast, significantly induced T and NK cell responses were associated with Ty21a vaccination, and integrative analysis indicated signatures reflecting amino acid metabolism with delayed onset of disease. Stimulation of PBMCs collected from participants prior to and following vaccination with the two vaccine strains in vitro confirmed the superior capacity of Ty21a to induce NK cells, validating gene expression results. These data provide insight into the effects of oral live attenuated typhoid vaccines on the human molecular immune response and underline the involvement of T cell response signatures with protection following challenge.
Project description:Rhesus macaques (RMs) inoculated with live-attenuated Rev-Independent Nef¯ simian immunodeficiency virus (Rev-Ind Nef¯SIV) as adults or neonates controlled viremia to undetectable levels and showed no signs of immunodeficiency over 6-8 years of follow-up. We tested the capacity of this live-attenuated virus to protect RMs against pathogenic, heterologous SIVsmE660 challenges
Project description:This SuperSeries is composed of the following subset Series: GSE39967: Transcriptional profiles of unfractionated lymph nodes cells obtained from completely protected, non protected and unvaccinated control rhesus macaques seven days prior to, and four and fourteen days after wt SIVmac239 challenge by microarray analysis. GSE39968: Transcriptional profiles of sorted CD8+ and CD4+ memory T cells from CP and NP and unvaccinated control RM 7 days prior to, and 4 and 14 days after wt SIVmac239 challenge by microarray analysis. Refer to individual Series
Project description:Live attenuated simian immunodeficiency virus (SIV) vaccines (LAVs) remain the most efficacious of all vaccines in nonhuman primate models of HIV and AIDS, yet the basis of their robust protection remains poorly understood. Here we show that the degree of LAV-mediated protection against intravenous wild-type SIVmac239 challenge strongly correlates with the magnitude and function of SIV-specific, effector-differentiated T cells in the lymph node but not with the responses of such T cells in the blood or with other cellular, humoral and innate immune parameters. We found that maintenance of protective T cell responses is associated with persistent LAV replication in the lymph node, which occurs almost exclusively in follicular helper T cells. Thus, effective LAVs maintain lymphoid tissue-based, effector-differentiated, SIV-specific T cells that intercept and suppress early wild-type SIV amplification and, if present in sufficient frequencies, can completely control and perhaps clear infection, an observation that provides a rationale for the development of safe, persistent vectors that can elicit and maintain such responses.
Project description:SIVmac239Δnef (SIVΔnef) live attenuated vaccine (LAV) induces the best protection among all the vaccine modalities tested in rhesus macaque model of HIV-1 infection. Time-dependent protection is a unique feature of this vaccine: macaques are not protected at 3-5 weeks post vaccination (WPV), whereas immune protection emerges between 15 and 20 WPV. To elucidate the protection mechanisms induced by SIVΔnef vaccine, we longitudinally compared the global gene expression profiles of SIV Gag-CM9+ CD8+ (Gag-specific CD8+) T cells from peripheral blood of Mamu-A*01 rhesus macaques at 3 and 20 WPV using rhesus microarray. We found that gene expression profiles of Gag-specific CD8+ T cells at 20 WPV are qualitatively different from those at 3 WPV. At 20 WPV, the most significant transcriptional changes of Gag-specific CD8+ T cells were genes involved in cell activation, differentiation and maturation toward central memory cells. Our study indicates that a higher quality of SIV-specific CD8+ T cells elicited by SIVΔnef over time may contribute to the maturation of time dependent protection.
Project description:Porcine epidemic diarrhea virus (PEDV) is a deadly coronavirus for neonatal piglets and no effective vaccines are available. Transcriptional regulatory sequences (TRSs) are critical in regulating coronavirus discontinuous transcription. Also, TRSs contribute to a high recombination rate of coronaviruses, leading to difficulty in developing safe live vaccines. We hypothesize that recoding the TRS core sequences (TRS-CS) of PEDV can make the recombination impossible between the engineered vaccine virus and field strains or wildtype viruses. We used an infectious clone-derived reporter PEDV, dORF3-EGFP, as the backbone to generate a remodeled TRS (RMT) mutant that carries the recoded leader and body TRS-CSs. The RMT and dORF3-EGFP showed comparable replication efficiency in Vero cells. However, the incompatibility between the rewired and wildtype TRS-CSs led to few EGFP in RMT-infected cells. Furthermore, RMT and dORF3-EGFP had a similar attenuated phenotype, replication efficiency, and protective immunogenicity in neonatal pigs. RNA sequencing analysis indicated that EGFP transcription directed by the heterogenous TRS-CSs was significantly reduced to an extremely low level. Meanwhile, recombinant viruses were not detected in Vero cells and in pigs that were co-infected with RMT and a PEDV S-INDEL strain, Iowa106. In vitro and in vivo passaging of the RMT did not result in reversion mutations in the rewired TRS-CSs, introduced gaps, and disrupted wildtype TRSs. In summary, the RMT mutant was resistant to recombination and genetically stable and can be further optimized (e.g., deletion of the EGFP) to serve as a platform to develop safe PEDV live attenuated vaccines.
Project description:Influenza B virus (IBV) is considered a major respiratory pathogen responsible for seasonal respiratory disease in humans, particularly severe in children and the elderly. Seasonal influenza vaccination is considered the most efficient strategy to prevent and control IBV infections. Live attenuated influenza virus vaccines (LAIVs) are thought to induce both humoral and cellular immune responses by mimicking a natural infection, but their effectiveness have recently come into question. Thus, the opportunity exists to find alternative approaches to improve overall influenza vaccine effectiveness. Two alternative IBV backbones were developed with re-arranged genomes, re-arranged M (FluB-RAM) and a re-arranged NS (FluB-RANS). Both re-arranged viruses showed temperature sensitivity in vitro compared to the WT type B/Bris strain, were genetically stable over multiple passages in embryonated chicken eggs and were attenuated in vivo in mice. In a prime-boost regime in naïve mice, both re-arranged viruses induced antibodies against HA with hemagglutination inhibition titers considered of protective value. In addition, antibodies against NA and NP were readily detected with potential protective value. Upon lethal IBV challenge, mice previously vaccinated with either FluB-RAM or FluB-RANS were completely protected against clinical disease and mortality. In conclusion, genome re-arrangement renders efficacious LAIV candidates to protect mice against IBV.