Directed attenuation to enhance vaccine immunity.
Ontology highlight
ABSTRACT:
SUBMITTER: Antia R
PROVIDER: S-EPMC7877766 | biostudies-literature | 2021 Feb
REPOSITORIES: biostudies-literature
Publications
Directed attenuation to enhance vaccine immunity.
Antia Rustom R Ahmed Hasan H Bull James J JJ
PLoS computational biology 20210201 2
Many viral infections can be prevented by immunizing with live, attenuated vaccines. Early methods of attenuation were hit-and-miss, now much improved by genetic engineering. However, even current methods operate on the principle of genetic harm, reducing the virus's ability to grow. Reduced viral growth has the undesired side-effect of reducing the host immune response below that of infection with wild-type. Might some methods of attenuation instead lead to an increased immune response? We use ...[more]
Similar Datasets
Project description:Lentivectors (LVs) have attracted considerable interest for their potential as a vaccine delivery vehicle. In this study, we evaluate in mice a dendritic cell (DC)-directed LV system encoding the Gag protein of human immunodeficiency virus (HIV) (LV-Gag) as a potential vaccine for inducing an anti-HIV immune response. The DC-directed specificity is achieved through pseudotyping the vector with an engineered Sindbis virus glycoprotein capable of selectively binding to the DC-SIGN protein. A single immunization by this vector induces a durable HIV Gag-specific immune response. We investigated the antigen-specific immunity and T-cell memory generated by a prime/boost vaccine regimen delivered by either successive LV-Gag injections or a DNA prime/LV-Gag boost protocol. We found that both prime/boost regimens significantly enhance cellular and humoral immune responses. Importantly, a heterologous DNA prime/LV-Gag boost regimen results in superior Gag-specific T-cell responses as compared with a DNA prime/adenovector boost immunization. It induces not only a higher magnitude response, as measured by Gag-specific tetramer analysis and intracellular IFN-gamma staining, but also a better quality of response evidenced by a wider mix of cytokines produced by the Gag-specific CD8(+) and CD4(+) T cells. A boosting immunization with LV-Gag also generates T cells reactive to a broader range of Gag-derived epitopes. These results demonstrate that this DC-directed LV immunization is a potent modality for eliciting anti-HIV immune responses.
| S-EPMC2777969 | biostudies-literature
Project description:Clinical studies of idiotype (Id) vaccination in patients with lymphoma have established a correlation between the induced anti-Id antibody responses and favorable clinical outcomes. To streamline the production of an Id vaccine, we engineered a small diabody (Db) molecule containing both a B-cell-targeting moiety (anti-CD19) and a lymphoma Id. This molecule (?CD19-Id) was designed to penetrate lymph nodes and bind to noncognate B cells to form an antigen presentation array. Indeed, the ?CD19-Id molecule accumulated on B cells in vivo after s.c. administration. These noncognate B cells, decorated with the diabody, could then stimulate the more rare Id-specific B cells. Peptide epitopes present in the diabody linker augmented the response by activating CD4(+) helper T cells. Consequently, the ?CD19-Id molecule induced a robust Id-specific antibody response and protected animals from tumor challenge. Such diabodies are produced in a cell-free protein expression system within hours of amplification of the specific Ig genes from the B-cell tumor. This customized product can now be available to vaccinate patients before they receive other, potentially immunosuppressive, therapies.
| S-EPMC3437846 | biostudies-other
Project description:Neoantigen vaccines aiming to induce tumor-specific T cell responses have achieved promising antitumor effects in early clinical trials. However, the underlying mechanism regarding response or resistance to this treatment is unclear. Here we observe that neoantigen vaccine-generated T cells can synergize with the immune checkpoint blockade for effective tumor control. Specifically, we performed single-cell sequencing on over 100,000 T cells and uncovered that combined therapy induces an antigen-specific CD8 T cell population with active chemokine signaling (Cxcr3+/Ccl5+), lower co-inhibitory receptor expression (Lag3-/Havcr2-) and higher cytotoxicity (Fasl+/Gzma+). Furthermore, generation of neoantigen-specific T cells in the draining lymph node is required for combination treatment. Signature genes of this unique population are associated with T cell clonal frequency and better survival in humans. Our study profiles the dynamics of tumor-infiltrating T cells during neoantigen vaccine and immune checkpoint blockade treatments and high-dimensionally identifies neoantigen-reactive T cell signatures for future development of therapeutic strategies.
| S-EPMC9050907 | biostudies-literature
Project description:Because of the continued emergence of SARS-CoV-2 variants, there has been considerable interest in how to display multivalent antigens efficiently. Bacterial outer membrane vesicles (OMVs) can serve as an attractive vaccine delivery system because of their self-adjuvant properties and the ability to be decorated with antigens. Here we set up a bivalent antigen display platform based on engineered OMVs using mCherry and GFP and demonstrated that two different antigens of SARS-CoV-2 could be presented simultaneously in the lumen and on the surface of OMVs. Comparing immunogenicity, ClyA-NG06 fusion and the receptor-binding domain (RBD) of the spike protein in the OMV lumen elicited a stronger humoral response in mice than OMVs presenting either the ClyA-NG06 fusion or RBD alone. Taken together, we provided an efficient approach to display SARS-CoV-2 antigens in the lumen and on the surface of the same OMV and highlighted the potential of OMVs as general multi-antigen carriers.
| S-EPMC9729586 | biostudies-literature
Project description:Exhaustion of CD8(+) T cells and upregulation of programmed death 1 (PD-1), a negative regulator of T cell activation, are characteristic features of individuals chronically infected with human immunodeficiency virus type 1. In a previous study, we showed in mice that a dendritic cell-directed lentiviral vector (DCLV) system encoding the human immunodeficiency virus (HIV)-1 Gag protein was an efficient vaccine modality to induce a durable Gag-specific T cell immune response. In this study, we demonstrate that blocking of the PD-1/PD-1 ligand (PD-L) inhibitory signal via an anti-PD-L1 antibody generated an enhanced HIV-1 Gag-specific CD8(+) immune response following both a single round of DCLV immunization and a homologous prime/boost regimen. The prime/boost regimen combined with PD-L1 blockade generated very high levels of Gag-specific CD8(+) T cells comprising several valuable features: improved ability to produce multiple cytokines, responding to a broader range of Gag-derived epitopes, and long-lasting memory. This enhanced cellular immune response generated by DCLV immunization combined with anti-PD-L1 blockade correlated with improved viral control following challenge with Gag-expressing vaccinia virus. Taken together, our studies offer evidence to support the use of PD-1/PD-L1 blockade as an adjuvant modality to enhance antigen-specific immune responses elicited by T cell-based immunizations such as DCLV.
| S-EPMC3437589 | biostudies-literature
Project description:The T cell specific RORγ isoform RORγt has been shown to be the key lineage-defining transcription factor to initiate the differentiation program of TH17 and TC17 cells, cells that have demonstrated antitumor efficacy. RORγt controls gene networks that enhance immunity including increased IL17 production and decreased immune suppression. Both synthetic and putative endogenous agonists of RORγt have been shown to increase the basal activity of RORγt enhancing TH17 cell proliferation. Here, we show that activation of RORγt using synthetic agonists drives proliferation of TH17 cells while decreasing levels of the immune checkpoint protein PD-1, a mechanism that should enhance antitumor immunity while blunting tumor associated adaptive immune resistance. Interestingly, putative endogenous agonists drive proliferation of TH17 cells but do not repress PD-1. These findings suggest that synthetic agonists of RORγt should activate TC17/TH17 cells (with concomitant reduction in the Tregs population), repress PD-1, and produce IL17 in situ (a factor associated with good prognosis in cancer). Enhanced immunity and blockage of immune checkpoints has transformed cancer treatment; thus such a molecule would provide a unique approach for the treatment of cancer.
| S-EPMC5178133 | biostudies-literature
Project description:Vibrio cholerae is a prototypical noninvasive mucosal pathogen, yet infection generates long-lasting protection against subsequent disease. Vibriocidal antibody responses are an imperfect but established correlate of protection against cholera following both infection and vaccination. However, vibriocidal antibody responses are likely a surrogate marker for longer-lasting functional immune responses that target the O-polysaccharide antigen at the mucosal surface. While the current bivalent inactivated oral whole cell vaccine is being increasingly used to prevent cholera in areas where the disease is a threat, the most significant limitation of this vaccine is it offers relatively limited direct protection in young children. Future strategies for cholera vaccination include the development of cholera conjugate vaccines and the further development of live attenuated vaccines. Ultimately, the goal of a multivalent vaccine for cholera and other childhood enteric infections that can be incorporated into a standard immunization schedule should be realized.
| S-EPMC6188552 | biostudies-other
Project description:Corynebacterium pseudotuberculosis, a gram-positive intracellular bacterial pathogen, is the etiological agent of the disease caseous lymphadenitis (CLA) in both sheep and goats. Attenuated mutants of C. pseudotuberculosis have the potential to act as novel live veterinary vaccine vectors. We have cloned and sequenced the aroB and aroQ genes from C. pseudotuberculosis C231. By allelic exchange, aroQ mutants of both C231, designated CS100, and a pld mutant strain TB521, designated CS200, were constructed. Infection of BALB/c mice indicated that introduction of the aroQ mutation into C231 and TB521 attenuated both strains. In sublethally infected BALB/c mice, both CS100 and CS200 were cleared from spleens and livers by day 8 postinfection. The in vivo persistence of these strains was increased when the intact aroQ gene was supplied on a plasmid in trans. Mice infected with TB521 harbored bacteria in organs at least till day 8 postinfection without ill effect. When used as a vaccine, only the maximum tolerated dose of CS100 had the capacity to protect mice from homologous challenge. Vaccination with TB521 also elicited protective immunity, and this was associated with gamma interferon (IFN-gamma) production from splenocytes stimulated 7 days postvaccination. The role of IFN-gamma in controlling primary infections with C. pseudotuberculosis was examined in mice deficient for the IFN-gamma receptor (IFN-gammaR(-/-) mice). IFN-gammaR(-/-) mice cleared an infection with CS100 but were significantly more susceptible than control littermates to infection with C231 or TB521. These studies support an important role for IFN-gamma in control of primary C. pseudotuberculosis infections and indicate that aroQ mutants remain attenuated even in immunocompromised animals. This is the first report of an aroQ mutant of a bacterial pathogen, and the results may have implications for the construction of aromatic mutants of Mycobacterium tuberculosis for use as vaccines.
| S-EPMC175430 | biostudies-other
Project description:The interaction of the immune system with cancer is complex, but new approaches are resulting in exciting therapeutic benefits. In order to enhance the immune response to cancer, immune therapies seek to either induce high avidity immune responses to tumour specific antigens or to convert the tumour to a more pro-inflammatory microenvironment. Strategies, including vaccination, oncolytic viruses, and adoptive cell transfer all seek to induce anti-tumour immunity. To overcome the suppressive tumour microenvironment checkpoint inhibitors and modulators of regulatory cell populations have been investigated. This review summarizes the recent advances in immune therapies and discusses the importance of combination therapies in the treatment of cancers.
| S-EPMC6027499 | biostudies-literature
Project description:The Spi1/ Pu.1 transcription factor plays a crucial role in myeloid cell development across many species. Several Spi1 target genes have been identified so far, yet the Spi1-dependent gene group remains largely unknown. To identify novel genes downstream of Spi1 we employed a microarray strategy using zebrafish embryos. We established the gene group down-regulated upon spi1 knockdown while simultaneously enriched in FACS-sorted embryonic myeloid cells of a spi1:GFP transgenic line, thus representing putative myeloid-specific Spi1 target genes. This gene group contained all previously identified Spi1-dependent zebrafish genes, confirming the validity of the approach, as well as novel immune-related genes. Colocalization studies with neutrophil and macrophage markers revealed that genes cxcr3.2, mpeg1, ptpn6 and mfap4 were expressed specifically in early embryonic macrophages. The analysis of adult zebrafish hematopoietic tissue showed that genes mfap4 and mpeg1 remained macrophage specific within the myeloid fraction throughout zebrafish life. We also demonstrated that gene cxcr3.2, coding for chemokine receptor 3.2, functions in macrophage migration to the site of bacterial infection. These results establish a myeloid-specific gene group dependent on Spi1 in zebrafish and identify novel early macrophage-specific marker genes, which will facilitate further studies of macrophage development and innate immune function. Zebrafish strains Zebrafish (Danio rerio) were handled in compliance with the local animal welfare regulations and maintained according to standard protocols (http://ZFIN.org). The spi1-gfp transgenic line used in this study (Pu1-lynEGFP, a gift from Franscesca Peri, EMBL, Heidelberg) contains 4 kb of spi1/pu.1 promoter sequence driving expression of membrane-targeted EGFP. Morpholino knock-down experiments Morpholino oligonucleotides (Gene Tools) were diluted to required concentration in 1x Danieu’s buffer (58 mM NaCl, 0.7 mM KCl, 0.4 mM MgSO4, 0.6 mM Ca(NO3)2, 5.0 mM HEPES; pH 7.6) containing 1% Phenol red (Sigma) and approximately 1 nl was injected into the 1-2 cell stage embryo using a Femtojet injector (Eppendorf). Embryo dissociation and FACS (Fluorescent activated cell sorting) Dissociation of embryos was performed according to Covassin et al. 30. In short, ~300 embryos of spi1:GFP line at 28 hpf were dechorionated by pronase treatment, rinsed in calcium free Ringer solution, followed by digestion with 0.25% trypsin. The obtained cell suspension was centrifuged, rinsed with PBS and resuspended in Leibovitz medium L15 without phenol red, 1% fetal calf serum, 0.8mM CaCl2, penicillin 50 U/ml and streptomycin 0.05 mg/ml. The single cell suspension was subject to FACS at room temperature using a FACSAria (Becton Dickinson) with the BD FACSDiva software version 5.0.3 and a Coherent Sapphire solid state laser 488 nm with 13 mW power. The GFP+ and GFP- cell fractions were collected separately into L15 medium supplemented with 0.8 mM CaCl2, 10% fetal calf serum and penicillin 50 U/ml and streptomycin 0.05 mg/ml. The standard yield from circa 300 embryos was approximately 2 x 105 GFP+ cells. Microarray experiment design and analysis Embryos injected either with 1 mM Pu1 morpholino19 or 1 mM Standard Control morpholino were harvested at 28 hours post fertilization (hpf). As a control, embryos injected with an equal volume of 1% Phenol red in Danieu’s buffer (1xPR/D) were used. Pools of 20-30 embryos were collected. RNA samples from spi1 morphants and standard control morphants were labelled with Cy5 and hybridized against a Cy3-labelled common reference (a mixture of all samples injected with 1xPR/D). This experiment was performed in triplicate. FACS sorted spi1-GFP zebrafish embryos at 28hpf were analyzed as follows: the RNA of GFP-positive fraction was labelled with Cy5 and hybridized against a Cy3-labelled RNA of corresponding GFP-negative fraction of cells from the same pool of embryos. This experiment was performed in duplicate. RNA isolation, synthesis of amino allyl labeled aRNA, coupling of Cy3 and Cy5 dyes, and hybridization conditions were as described31. Microarray analysis was performed using custom-designed 44k Agilent chips (platform accession number in GEO: GPL7735) described elsewhere 31. Microarray data were processed and analyzed as described 31. Significance cut-offs for differentially expressed probe sequences were set at 1.2 fold change at P <10-2.
2010-04-30 | E-GEOD-19206 | biostudies-arrayexpress