Biology subjects

BenMohamed, L.

Publications and source records attributed to BenMohamed, L..

5 recordsLinked to original sources

bioRxiv2022

Dysfunctional Senescent Herpes Simplex Virus Specific CD57+CD8+ T cells are Associated with Recurrent Symptomatic Herpes in Humans

Herpes simplex virus (HSV)-specific CD8+ T cells protect mice from herpes infection and disease. However, the phenotype and function of HSV-specific CD8+ T cells that play a key role in the "natural" protection seen in HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. We previously reported that symptomatic (SYMP) patients (who have frequent bouts of recurrent herpes disease) had more less-differentiated and dysfunctional HSV-specific CD8+ T cells. In contrast, healthy ASYMP individuals maintained a significantly higher proportion of differentiated polyfunctional CD8+ T cells. Here we report that, HSV-specific CD8+ T cells from SYMP patients, but not from ASYMP individuals, have phenotypic and functional characteristics of cellular senescence, including: (i) high frequency of senescent (CD57+) and exhausted (PD-1+) CD8+ T cells; (ii) late terminally differentiated (KLRG1+), non-proliferating CD8+ T cells; (iii) HSV-specific CD8+ T cells were declined overtime and were not maintained homeostatistically (CD127+CD8+ T cells); (iv) loss of co-stimulatory molecule (CD28) on HSV-specific CD8+ T cells; (v) decreased production of effector molecules (granzyme B and perforin) by HSV-specific CD8+ T cells. Our findings provide insights into the role of senescence in HSV-specific CD8+ T cells in susceptibility to recurrent herpes and have implications for T-cell-based immunotherapeutic strategies against recurrent herpes in humans. IMPORTANCEReactivation of herpes simplex virus 1 (HSV-1) from latency leads to recurrent herpetic disease in symptomatic (SYMP) individuals. A role of T cells in herpes immunity against recurrent herpetic disease is established. However, the phenotype and function of HSV-specific CD8+ T cells that play a key role in the "natural" protection seen in HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In the present study, we report that, HSV-specific CD8+ T cells from SYMP patients, but not from ASYMP individuals, have phenotypic and functional characteristics of cellular senescence. Our findings provide insights into the role of senescence in HSV-specific CD8+ T cells in susceptibility to recurrent herpes and have implications for T-cell-based immunotherapeutic strategies against recurrent herpes in humans.

immunology↗

bioRxiv2022

Age-Related Impairment of Innate and Adaptive Immune Responses Following Intranasal Herpes Simplex Infection

Immune function declines with age, leading to an increased vulnerability to respiratory viral infections. The mechanisms by which aging negatively impacts the innate and adaptive immune system leading to enhanced susceptibility to infections remain to be fully elucidated. In the present study, we used a mouse model of intranasal infection with herpes simplex virus type 1 (HSV-1), a virus that can enter the lungs through the nasal route causing pneumonia, a serious health concern in the elderly. Following intranasal inoculation of young (6 weeks), adult (36 weeks), and aged (68 weeks) with HSV-1 (KOS strain) we: (i) compared the local and systemic innate and adaptive immune response to infection; and (ii) correlated the level and type of immune response to protection against HSV-1 infection. Compared to young and adult mice, aged mice displayed: (i) increased basal level activation of epithelial cells with a decreased expression of TLR3; (ii) increased activation of dendritic cells with increased expression of MHC-1, MHC-II and CD80/86; and (iii) decreased production of type-I interferons upon stimulation; (iv) a delay in cytokines and chemokines production in the lungs; and (v) an impairment in function (CD107 and IFN-{gamma} production) of HSV-specific CD8+ T cells. These impairment in innate and adaptive immune responses in aged mice following intranasal HSV-1 inoculation was associated with symptomatic herpes infection. The findings suggest an age-related impairment of both innate and adaptive immune responses which may exacerbate herpes infection and disease in the elderly. IMPORTANCEImmune function declines with age, leading to an increased vulnerability of the elderly to respiratory viral infections. The mechanisms by which aging negatively impacts the innate and adaptive immune system leading to enhanced susceptibility to respiratory infections remain to be fully elucidated. The present study showed that, compared to young and adult mice, aged mice displayed increased basal level activation of epithelial cells with a decreased expression of TLR3 increased activation of dendritic cells associated with an impairment of HSV-specific CD8+ T cell responses. These immune dysregulations were associated with to symptomatic herpes infection. The findings suggest an age-related impairment of both innate and adaptive immune responses which may exacerbate herpes infection and disease in the elderly.

immunology↗

bioRxiv2021

Antiviral CD19+CD27+ Memory B Cells Are Associated with Protection from Recurrent Asymptomatic Ocular Herpes Infection

Reactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity seen in asymptomatic (ASYMP) individuals is heavily explored, the role of B cells is less investigated. In the present study, we evaluated whether B cells are associated with protective immunity against recurrent ocular herpes. The frequencies of circulating HSV-specific memory B cells and of memory follicular helper T cells (CD4+ Tfh cells), that help B cells produce antibodies, were compared between HSV-1 infected SYMP and ASYMP individuals. The levels of IgG/IgA and neutralizing antibodies were compared in SYMP and ASYMP individuals. We found that: (i) the ASYMP individuals had increased frequencies of HSV-specific CD19+CD27+ memory B cells; and (ii) high frequencies of HSV-specific switched IgG+CD19+CD27+ memory B cells detected in ASYMP individuals were directly proportional to high frequencies of CD45R0+CXCR5+CD4+ memory Tfh cells. However, no differences were detected in the level of HSV-specific IgG/IgA antibodies in SYMP and ASYMP individuals. Using the UV-B-induced HSV-1 reactivation mouse model, we found increased frequencies of HSV-specific antibody-secreting plasma HSV-1 gD+CD138+ B cells within the TG and circulation of ASYMP mice compared to SYMP mice. In contrast, no significant differences in the frequencies of B cells were found in the cornea, spleen, and bone-marrow. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from symptomatic recurrent ocular herpes. IMPORTANCEReactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity against blinding recurrent herpetic disease is heavily explored, the role of B cells is less investigated. In the present study, we found that in both asymptomatic (ASYMP) individuals and ASYMP mice there was increased frequencies of HSV-specific memory B cells that were directly proportional to high frequencies of memory Tfh cells. Moreover, following UV-B induce reactivation, we found increased frequencies of HSV-specific antibody-secreting plasma B cells within the TG and circulation of ASYMP mice, compared to SYMP mice. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from recurrent ocular herpes.

immunology↗

bioRxiv2020

Healing of Primary and Recurrent Mouse Ocular Herpetic Disease Following Topical Ocular Treatment with an Engineered Fibroblast Growth Factor-1 (FGF-1) is Associated with Increased Frequency and Function of Corneal Anti-Inflammatory M2 Macrophages

Herpes simplex virus 1 (HSV-1) infects the cornea and caused blinding ocular disease. In the present study, we evaluated whether and how a novel engineered version of fibroblast growth factor-1 (FGF-1), designated as TTHX1114, would reduce the severity of HSV-1-induced primary and recurrent ocular herpes in the mouse model. The efficacy of TTHX1114 against corneal keratopathy was assessed in B6 mice following corneal infection with HSV-1, strain McKrae. Starting day one post infection (PI), mice received TTHX1114 for 14 days. The severity of primary stromal keratitis and blepharitis were monitored up to 28 days PI. Inflammatory cell infiltrating infected corneas were characterized up to day 21 PI. The severity of recurrent herpetic disease was quantified in latently infected B6 mice up to 30 days post-UVB corneal exposure. The effect of TTHX1114 on M1 and M2 macrophage polarization was determined in vivo in mice and in vitro on primary human monocytes-derived macrophages. Compared to HSV-1 infected non-treated mice, the infected and TTHX1114 treated mice exhibited a significant reduction of primary and recurrent stromal keratitis and blepharitis, without affecting virus corneal replication. The therapeutic effect of TTHX1114 was associated with a significant decrease in the frequency of M1 macrophages infiltrating the cornea, which expressed significantly lower levels of pro-inflammatory cytokines and chemokines. This polarization toward M2 phenotype was confirmed in vitro on human primary macrophages. This pre-clinical finding suggests use of this engineered FGF-1 as a novel immunotherapeutic regimen to reduce primary and recurrent HSV-1-induced corneal disease in the clinic. IMPORTANCEHerpes Simplex Virus type 1 (HSV-1) is a prevalent human pathogen that infects the cornea causing potentially blinding herpetic disease. The present study is the first to demonstrate a reduction of primary and recurrent corneal herpetic disease in mice following engineered FGF-1 (TTHX1114) treatment. This was associated with a decrease of pro-inflammatory M1 macrophages and an increase of anti-inflammatory M2 macrophages infiltrating the corneas of HSV-1 infected mice. The finding in mice were confirmed in humans by showing that in vitro FGF-1 treatment skewed the polarization of primary monocyte-derived macrophages into the anti-inflammatory M2 phenotype. Moreover, FGF-1 treatment appeared to reduce production of anti-inflammatory mediators. This pre-clinical finding support this engineered FGF-1 as a novel immunotherapeutic regimen to reduce primary and recurrent corneal herpetic disease in the clinic.

immunology↗

bioRxiv2020

Genome-Wide Asymptomatic B-Cell, CD4+ and CD8+ T-Cell Epitopes, that are Highly Conserved Between Human and Animal Coronaviruses, Identified from SARS-CoV-2 as Immune Targets for Pre-Emptive Pan-Coronavirus Vaccines

Over the last two decades, there have been three deadly human outbreaks of Coronaviruses (CoVs) caused by emerging zoonotic CoVs: SARS-CoV, MERS-CoV, and the latest highly transmissible and deadly SARS-CoV-2, which has caused the current COVID-19 global pandemic. All three deadly CoVs originated from bats, the natural hosts, and transmitted to humans via various intermediate animal reservoirs. Because there is currently no universal pan-Coronavirus vaccine available, two worst-case scenarios remain highly possible: (1) SARS-CoV-2 mutates and transforms into a seasonal "flu-like" global pandemic; and/or (2) Other global COVID-like pandemics will emerge in the coming years, caused by yet another spillover of an unknown zoonotic bat-derived SARS-like Coronavirus (SL-CoV) into an unvaccinated human population. Determining the antigen and epitope landscapes that are conserved among human and animal Coronaviruses as well as the repertoire, phenotype and function of B cells and CD4+ and CD8+ T cells that correlate with resistance seen in asymptomatic COVID-19 patients should inform in the development of pan-Coronavirus vaccines 1. In the present study, using several immuno-informatics and sequence alignment approaches, we identified several human B-cell, CD4+ and CD8+ T cell epitopes that are highly conserved in: (i) greater than 81,000 SARS-CoV-2 human strains identified to date in 190 countries on six continents; (ii) six circulating CoVs that caused previous human outbreaks of the "Common Cold"; (iii) five SL-CoVs isolated from bats; (iv) five SL-CoV isolated from pangolins; (v) three SL-CoVs isolated from Civet Cats; and (vi) four MERS strains isolated from camels. Furthermore, we identified cross-reactive asymptomatic epitopes that: (i) recalled B cell, CD4+ and CD8+ T cell responses from both asymptomatic COVID-19 patients and healthy individuals who were never exposed to SARS-CoV-2; and (ii) induced strong B cell and T cell responses in "humanized" Human Leukocyte Antigen (HLA)-DR/HLA-A*02:01 double transgenic mice. The findings herein pave the way to develop a pre-emptive multi-epitope pan-Coronavirus vaccine to protect against past, current, and potential future outbreaks.

immunology↗