Efficient immune responses in immunocompetent individuals developing symptomatic CMV infection
Ontology highlight
ABSTRACT: Primary human cytomegalovirus (HCMV) infection usually goes unnoticed, causing mild or no symptoms in immunocompetent individuals. Some rare severe clinical cases have however been reported without investigation of host immune responses or viral virulence. In this present study, we investigate, for the first time, phenotypic and functional features together with gene expression profiles in immunocompetent adults experiencing a severe primary HCMV infection. Twenty PHIP were enrolled as well as 26 HCMV-seronegative and 39 HCMV-seropositive healthy controls. PHIP had a huge lymphocytosis marked by massive expansion of NK and T cell compartments. Interestingly, PHIP mounted efficient innate and adaptive immune responses with a deep HCMV imprint, revealed mainly by the expansion of NKG2C+ NK cells, CD16+ V2- T cells and conventional HCMV-specific CD8+ T cells. The main effector lymphocytes were activated and displayed an early immune phenotype that developed toward a more mature differentiated status. We suggest that both huge lymphocytosis and excessive lymphocyte activation could contribute to a massive cytokine production known to mediate tissue damage observed in PHIP. Taken together, these findings bring new insights into the comprehensive understanding of immune mechanisms involved during primary HCMV-infection in immunocompetent individuals.
Project description:The latent human Cytomegalovirus (hCMV) infection can pose a serious threat of reactivation and disease occurrence in immune-compromised individuals, as well as burdens the immune system in immune-competent individuals. Though, T cells are at the core of the protective immune response to hCMV infection, a detailed characterization of different T cell subsets involved in protection against the hCMV infection is lacking. Here we analyzed the single-cell transcriptomes and the single-cell T cell antigen receptor (TCR) repertoires of over 8000 hCMV-reactive peripheral T cells isolated from different memory compartments. The hCMV-reactive T cells were highly heterogeneous and consisted of different developmental memory and functional T cell subsets such as, the long-term memory precursors and effectors, T helper-17, T regulatory cells (TREGs) and cytotoxic T lymphocytes (CTLs). The hCMV-antigen specific TREGs were enriched for molecules linked to their suppressive function and interferon response genes. The CTLs were of two types, the pre-effector and effector like. Of particular interest was the mixture of both CD4-CTLs and CD8-CTLs in both the pre-effector and effector cytotoxic clusters, suggesting that both CD4-CTLs and CD8-CTLs share transcriptomic signatures. The huge TCR clonal expansion of both the cytotoxic clusters imply their predominant role in protective immune response to CMV. Further the clonotype sharing between the CTL clusters and the long-term memory clusters, indicate potential progenitors of CD4-CTLs. Together our study has identified many subsets of hCMV-specific memory T cells that may have implication in better understanding the hCMV-specific T cell immunity to design vaccination strategies and therapeutics.
Project description:Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal TCRalphabeta+/CD4+/NKa+/CD8-/+dim T-large granular lymphocyte (LGL) lymphocytosis. Since healthy individuals show (oligo)clonal expansions of hCMV-specific TCRVbeta+/CD4+/cytotoxic/memory T-cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+ T-LGL. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile (GEP) analysis. Experiment Overall Design: Total RNA was isolated from magnetic-activated cell sorter (MACS)-freshly purified hCMV-stimulated CD69+, hCMV-stimulated CD69- and unstimulated monoclonal CD4+ T-LGL lymphocytes from PB samples from four TCRVbeta+/CD4+ T-LGL lymphocytosis patients (purity of �98%). Briefly, 100 ng of total RNA from each of the 12 purified cell fractions was amplified and labeled using the GeneChip two cycle cDNA synthesis kit and the GeneChip IVT labeling kit (Affymetrix Inc., Santa Clara, CA), respectively. Then it was hybridized to the Human Genome U133 Plus 2.0 Array (Affymetrix). Experiment Overall Design: In parallel, total RNA was also isolated from highly purified (� 98% purity) hCMV-stimulated (specific) CD69+ CD4+ T-lymphocytes isolated from PB samples from hCMV-seropositive healthy donors (n=5, mean age of 36 years) using a FACSAria flow cytometer (BDB). To get pure and highly concentrated RNA, the silica membrane technology NucleoSpin® RNA XS (Macherey-Nagel, Düren, Germany) was used. Total RNA was then amplified, labeled and hybridized to the Human Genome U133 Plus 2.0 Array (Affymetrix) as described above.
Project description:Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal TCRalphabeta+/CD4+/NKa+/CD8-/+dim T-large granular lymphocyte (LGL) lymphocytosis. Since healthy individuals show (oligo)clonal expansions of hCMV-specific TCRVbeta+/CD4+/cytotoxic/memory T-cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+ T-LGL. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile (GEP) analysis.
Project description:Primary infection with human cytomegalovirus (HCMV) results in a lifelong infection due to its ability to establish latent infection, with one characterized viral reservoir being hematopoietic cells. Although reactivation from latency causes serious disease in immunocompromised individuals, our molecular understanding of latency is limited. Here, we delineate viral gene expression during natural HCMV persistent infection by analyzing the massive transcriptome sequencing (RNA-seq) atlas generated by the Genotype-Tissue Expression (GTEx) project. This systematic analysis reveals that HCMV persistence in vivo is prevalent in diverse tissues. Notably, we find only viral transcripts that resemble gene expression during various stages of lytic infection with no evidence of any highly restricted latency-associated viral gene expression program. To further define the transcriptional landscape during HCMV latent infection, we also used single-cell RNA-seq and a tractable experimental latency model. In contrast to some current views on latency, we also find no evidence for any highly restricted latency-associated viral gene expression program. Instead, we reveal that latency-associated gene expression largely mirrors a late lytic viral program, albeit at much lower levels of expression. Overall, our work has the potential to revolutionize our understanding of HCMV persistence and suggests that latency is governed mainly by quantitative changes, with a limited number of qualitative changes, in viral gene expression.
Project description:Human cytomegalovirus (HCMV) is a widespread virus and can establish life-long latent infection in large populations. In order to establish persistent and latent infection in healthy individuals, HCMV encodes a large array of proteins that can modulate different components and pathways of host cells. It has been reported that pUL138 encoded by UL133-UL138 polycistronic locus promotes a latent infection in primary CD34+ HPCs infected in vitro. In this study, a recombinant HCMV, namely HanUL138del, was constructed by deleting the UL138 locus of Han, a clinic HCMV strain. Then a comparative quantitative proteomic analysis of Han and HanUL138del infected MRC5 cells was performed, aiming to study the effect of pUL138 on host cell in the context of HCMV infection. Our result indicated that at the early phase of HCMV infection, innate immune response was differentially activated, while at late phase of HCMV infection, multiple host proteins were differentially expressed, between Han or HanUL138del infected cells.
Project description:Human cytomegalovirus (hCMV) is a highly prevalent pathogen that, upon primary infection, establishes life-long persistence in all infected individuals. Acute hCMV infections cause a variety of diseases in humans with developmental or acquired immune deficits. In addition, persistent hCMV infection may contribute to various chronic disease conditions even in immunologically normal people. The pathogenesis of hCMV disease has been frequently linked to inflammatory host immune responses triggered by virus-infected cells. Moreover, hCMV infection activates numerous host genes many of which encode pro-inflammatory proteins. However, little is known about the relative contributions of individual viral gene products to these changes in cellular transcription. We systematically analyzed the effects of the hCMV 72-kDa immediate-early 1 (IE1) protein, a major transcriptional activator and antagonist of type I interferon (IFN) signaling, on the human transcriptome. Following expression under conditions closely mimicking the situation during productive infection, IE1 elicits a global type II IFN-like host cell response. This response is dominated by the selective up-regulation of immune stimulatory genes normally controlled by IFN-gamma and includes the synthesis and secretion of pro-inflammatory chemokines. IE1-mediated induction of IFN-stimulated genes strictly depends on tyrosine-phosphorylated signal transducer and activator of transcription 1 (STAT1) and correlates with the nuclear accumulation and sequence-specific binding of STAT1 to IFN-gamma-responsive promoters. However, neither synthesis nor secretion of IFN-gamma or other IFNs seems to be required for the IE1-dependent effects on cellular gene expression. Our results demonstrate that a single hCMV protein can trigger a pro-inflammatory host transcriptional response via an unexpected STAT1-dependent but IFN-independent mechanism and identify IE1 as a candidate determinant of hCMV pathogenicity. We used a total of 18 microarrays for analyzing triplicate samples each of IE1-negative control fibroblasts (TetR cells) without induction (3 arrays), fibroblasts containing inducible IE1 (TetR-IE1 cells) without induction (3 arrays), TetR cells induced for 24 h (3 arrays), TetR-IE1 cells induced for 24 h (3 arrays), TetR cells induced for 72 h (3 arrays), and TetR-IE1 cells induced for 72 h (3 arrays)
Project description:Congenital cytomegalovirus (cCMV) is the most common intrauterine infection, leading to infant neurodevelopmental disabilities. An improved knowledge of correlates of protection against cCMV is needed to guide prevention strategies. Here, we employed a unique ex vivo model of human CMV (HCMV) infection in decidual tissues of women with and without preconception immunity, recapitulating nonprimary versus primary infection at the authentic maternofetal transmission site. We showed that decidual tissues of women with preconception immunity exhibited intrinsic resistance to HCMV, mounting a rapid activation of tissue resident memory CD8+ and CD4+ T cells upon nonprimary infection. We further revealed the role of HCMV-specific decidual-tissue resident CD8+ T cells in local protection against nonprimary HCMV infection. The findings could inform the development of vaccine against cCMV, and provide insights for further studies of the integrity of immune defense against cCMV and other pathogens in the human maternal-fetal interface.
Project description:Congenital human cytomegalovirus (HCMV) infection is the leading infectious cause of birth defects, including neurodevelopmental disorders. HCMV infection mainly targets neural progenitor cells (NPCs) in fetal brains, inducing abnormal differentiation by altering key regulatory pathways. HCMV expresses a series of viral miRNAs during infection, but their roles, particularly in NPCs, are not fully understood. In this study, we characterized expression profiles of both cellular and viral miRNAs in HCMV-infected NPCs by microarray analysis during early infection time points and investigated the primary effects of these miRNAs on regulating NPC fate. While expression of most cellular miRNAs was unaffected by HCMV infection, one cellular miRNA was upregulated and six were downregulated from 2 to 24 h post infection. Moreover, of 17 HCMV miRNAs evaluated, six were differentially expressed in HCMV-infected NPCs during early infection time points.
Project description:HCMV -treated and control human adult neural precurso cells (NPC) were used to extract RNA for profiling on DNA arrays Primary adult hippocampus-derived neural precursor cells were used at passage # 2-4 for HCMV infection, followed by RNA extraction at indicated times Primary adult neural precursor cells were infected with HCMV strains Towne and TR (O.1MOI) and RNA was extracted at 72 hrs postinfection for expression profiling on both HCMV and Affymetrix DNA arrays
Project description:Human cytomegalovirus (HCMV) is a major human pathogen whose life-long persistence is enabled by its remarkable capacity to systematically subvert host immune defences. In exploring the finding that HCMV infection upregulates tumor necrosis factor receptor 2 (TNFR2), a ligand for the proinflammatory anti-viral cytokine TNFa, we discovered the underlying mechanism was due to targeting of the protease, A Disintegrin And Metalloproteinase 17 (ADAM17). ADAM17 is the prototype ‘sheddase, a family of proteases that cleaves other membrane-bound proteins to release biologically active ectodomains into the supernatant. HCMV impaired ADAM17 surface expression through the action of two virally-encoded proteins in its UL/b’ region, UL148 and UL148D. Proteomic plasma membrane profiling of cells infected with a HCMV double deletion mutant for UL148 and UL148D with restored ADAM17 expression, combined with ADAM17 functional blockade, showed that HCMV stabilized the surface expression of 114 proteins (p<0.05) in an ADAM17-dependent fashion. These included known substrates of ADAM17 with established immunological functions such as TNFR2 and Jagged1, but also numerous novel host and viral targets, such as Nectin1, UL8 and UL144. Regulation of TNFa-induced cytokine responses and NK inhibition during HCMV infection were dependent on this impairment of ADAM17. We therefore identify a viral immunoregulatory mechanism in which targeting a single sheddase enables broad regulation of multiple critical surface receptors, revealing a paradigm for viral-encoded immunomodulation.