Dataset Information

Human Cytomegalovirus (HCMV)-infected Astrocytoma Cells Impair the Function of HCMV-specific Cytotoxic T Cells.

ABSTRACT:

Background

Human cytomegalovirus (HCMV) infection in glioblastoma multiforme (GBM) is associated with a poor prognosis and may affect the pathogenesis of GBM. In this study, we investigated the role of HCMV-infected astrocytoma cells in impairing the activity of cytotoxic T lymphocytes (CTLs) specific to the HCMV protein.

Methods

CTLs specific to HCMV immediate early (IE)-1 were expanded from peripheral blood mononuclear cells of healthy donors by stimulating CD8+ T lymphocytes with U373MG cells (ATCC HTB-17: male) expressing HCMV IE-1. The death rate of the target and the effector cells was determined by the total count of the remaining respective cells after the interaction of them.

Results

The death rate of the target cells by CTLs increased depending on HLA restriction and the effector:target (E:T) ratio. The death rate of effector cells in the HCMV-infected U373MG cell culture was 37.1% on day 4 post-infection. The removal of the culture supernatant from HCMV-infected U373MG cells prior to adding the effector cells increased target cell death from 8.4% to 40.8% at E:T = 1:1, but not at E:T = 3:1. The transfer of cells from a 24-hour co-culture of the HCMV-infected U373MG cells and CTLs to HCMV IE-1-expressing target cells resulted in decreasing the cell death rate of the target cells from 31.1% to 13.0% at E:T = 1:1, but not at E:T = 3:1. HCMV infection of U373MG cells decreases the activity of CTLs specific to HCMV when the number of CTLs is low.

Conclusion

These results suggest that HCMV could impair CTL activity and facilitate glioblastoma growth unchecked by CTLs.

SUBMITTER: Kim J

PROVIDER: S-EPMC7358065 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Publications

Human Cytomegalovirus (HCMV)-infected Astrocytoma Cells Impair the Function of HCMV-specific Cytotoxic T Cells.

Kim Jiyeon J Lee Won Woo WW Hwang Eung Soo ES

Journal of Korean medical science 20200713 27

<h4>Background</h4>Human cytomegalovirus (HCMV) infection in glioblastoma multiforme (GBM) is associated with a poor prognosis and may affect the pathogenesis of GBM. In this study, we investigated the role of HCMV-infected astrocytoma cells in impairing the activity of cytotoxic T lymphocytes (CTLs) specific to the HCMV protein.<h4>Methods</h4>CTLs specific to HCMV immediate early (IE)-1 were expanded from peripheral blood mononuclear cells of healthy donors by stimulating CD8+ T lymphocytes wi ...[more]

PMID: 32657085

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Project description:Human cytomegalovirus (HCMV) infection and periodic reactivation are generally well controlled by the HCMV-specific T cell response in healthy people. While the CD8+ T cell response to HCMV has been extensively studied, the HCMV-specific CD4+ T cell effector response is not as well understood, especially in the context of direct interactions with HCMV-infected cells. We screened the gamma interferon (IFN-γ) and interleukin-10 (IL-10) responses to 6 HCMV peptide pools (pp65, pp71, IE1, IE2, gB, and US3, selected because they were the peptides most frequently responded to in our previous studies) in 84 donors aged 23 to 74 years. The HCMV-specific CD4+ T cell response to pp65, IE1, IE2, and gB was predominantly Th1 biased, with neither the loss nor the accumulation of these responses occurring with increasing age. A larger proportion of donors produced an IL-10 response to pp71 and US3, but the IFN-γ response was still dominant. CD4+ T cells specific to the HCMV proteins studied were predominantly effector memory cells and produced both cytotoxic (CD107a expression) and cytokine (macrophage inflammatory protein 1β secretion) effector responses. Importantly, when we measured the CD4+ T cell response to cytomegalovirus (CMV)-infected dendritic cells in vitro, we observed that the CD4+ T cells produced a range of cytotoxic and secretory effector functions, despite the presence of CMV-encoded immune evasion molecules. CD4+ T cell responses to HCMV-infected dendritic cells were sufficient to control the dissemination of virus in an in vitro assay. Together, the results show that HCMV-specific CD4+ T cell responses, even those from elderly individuals, are highly functional and are directly antiviral.IMPORTANCE Human cytomegalovirus (HCMV) infection is carried for a lifetime and in healthy people is kept under control by the immune system. HCMV has evolved many mechanisms to evade the immune response, possibly explaining why the virus is never eliminated during the host's lifetime. The dysfunction of immune cells associated with the long-term carriage of HCMV has been linked with poor responses to new pathogens and vaccines when people are older. In this study, we investigated the response of a subset of immune cells (CD4+ T cells) to HCMV proteins in healthy donors of all ages, and we demonstrate that the functionality of CD4+ T cells is maintained. We also show that CD4+ T cells produce effector functions in response to HCMV-infected cells and can prevent virus spread. Our work demonstrates that these HCMV-specific immune cells retain many important functions and help to prevent deleterious HCMV disease in healthy older people.

Project description:We have established that human cytomegalovirus (HCMV) infection modulates the biology of target primary blood monocytes, allowing HCMV to use monocytes as 'vehicles' for its systemic spread. HCMV infection of monocytes results in rapid induction of PI(3)K and NF-kB activity. Integrins, which are upstream of the PI(3)K and NF-kB pathways, were shown to be involved in HCMV binding to and entry into fibroblasts, suggesting that receptor-ligand-mediated signaling following viral binding to integrins on monocytes could trigger the functional changes seen in infected monocytes. We now show that integrin engagement and the activation of the integrin/Src-signaling pathway is essential for the induction of HCMV-infected monocyte motility. To investigate how integrin engagement by HCMV triggers monocyte motility, we examined the infected monocyte transcriptome and found that the integrin/Src-signaling pathway regulates the expression of paxillin, which is an important signal transducer in the regulation of actin rearrangement during cell adhesion and movement. Functionally, we observed that paxillin is activated via the integrin/Src-signaling pathway and is required for monocyte motility. Because motility is intimately connected to cellular cytoskeletal organization, a process that is also important in viral entry, we investigated the role paxillin regulation plays in the process of viral entry of monocytes. New results confirmed that HCMV`s ability to enter target monocytes is significantly inhibited in cells deficient in paxillin expression or that had their integrin/Src/paxillin signaling pathway blocked. From our data, HCMV-cell interactions emerge as an essential trigger for the cellular changes that allow for HCMV entry and hematogenous dissemination. Monocytes were mock-infected, HCMV-infected, or pretreated with PP2 inhibitor prior to HCMV infection. There were three samples analyzed per individual replicate. Three replicates are included. comparative studies with a use of the specific Src kinase activity inhibitor

Dataset Information

Human Cytomegalovirus (HCMV)-infected Astrocytoma Cells Impair the Function of HCMV-specific Cytotoxic T Cells.

Background

Methods

Results

Conclusion

Publications

Human Cytomegalovirus (HCMV)-infected Astrocytoma Cells Impair the Function of HCMV-specific Cytotoxic T Cells.

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