Biology subjects

Greene, W. C.

Publications and source records attributed to Greene, W. C..

8 recordsLinked to original sources

bioRxiv2021

Deep Phenotypic Analysis of Blood and Lymphoid T and NK Cells from HIV+ Controllers and Non-Controllers

T and natural killer (NK) cells are effector cells with key roles in anti-HIV immunity, including in lymphoid tissues, the major site of HIV persistence. In this study, we used 42-parameter CyTOF to conduct deep phenotyping of paired blood- and lymph node (LN)-derived T and NK cells from three groups of HIV+ aviremic individuals: elite controllers, and antiretroviral therapy (ART)-suppressed individuals who had started therapy during chronic vs. acute infection, the latter of which is associated with better outcomes. We found that acute-treated individuals are enriched for specific subsets of T and NK cells, including blood-derived CD56-CD16+ NK cells previously associated with HIV control, and LN-derived CD4+ T follicular helper cells with heightened expansion potential. An in-depth comparison of the features of the cells from blood vs. LNs of individuals from our cohort revealed that T cells from blood were more activated than those from LNs. By contrast, LNs were enriched for follicle-homing CXCR5+ CD8+ T cells, which expressed increased levels of inhibitory receptors and markers of survival and proliferation as compared to their CXCR5-counterparts. In addition, a subset of memory-like CD56brightTCF1+ NK cells was enriched in LNs relative to blood. These results together suggest unique T and NK cell features in acute-treated individuals, and highlight the importance of examining effector cells not only in blood but also the lymphoid tissue compartment, where the reservoir mostly persists, and where these cells take on distinct phenotypic features.

immunology↗

bioRxiv2021

SARS-CoV-2 spike protein induces abnormal inflammatory blood clots neutralized by fibrin immunotherapy

Blood clots are a central feature of coronavirus disease-2019 (COVID-19) and can culminate in pulmonary embolism, stroke, and sudden death. However, it is not known how abnormal blood clots form in COVID-19 or why they occur even in asymptomatic and convalescent patients. Here we report that the Spike protein from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to the blood coagulation factor fibrinogen and induces structurally abnormal blood clots with heightened proinflammatory activity. SARS-CoV-2 Spike virions enhanced fibrin-mediated microglia activation and induced fibrinogen-dependent lung pathology. COVID-19 patients had fibrin autoantibodies that persisted long after acute infection. Monoclonal antibody 5B8, targeting the cryptic inflammatory fibrin epitope, inhibited thromboinflammation. Our results reveal a procoagulant role for the SARS-CoV-2 Spike and propose fibrin-targeting interventions as a treatment for thromboinflammation in COVID-19. One-Sentence SummarySARS-CoV-2 spike induces structurally abnormal blood clots and thromboinflammation neutralized by a fibrin-targeting antibody.

immunology↗

bioRxiv2021

mRNA vaccine-induced SARS-CoV-2-specific T cells recognize B.1.1.7 and B.1.351 variants but differ in longevity and homing properties depending on prior infection status

While mRNA vaccines are proving highly efficacious against SARS-CoV-2, it is important to determine how booster doses and prior infection influence the immune defense they elicit, and whether they protect against variants. Focusing on the T cell response, we conducted a longitudinal study of infection-naive and COVID-19 convalescent donors before vaccination and after their first and second vaccine doses, using a high-parameter CyTOF analysis to phenotype their SARS-CoV-2-specific T cells. Vaccine-elicited spike-specific T cells responded similarly to stimulation by spike epitopes from the ancestral, B.1.1.7 and B.1.351 variant strains, both in terms of cell numbers and phenotypes. In infection-naive individuals, the second dose boosted the quantity and altered the phenotypic properties of SARS-CoV-2-specific T cells, while in convalescents the second dose changed neither. Spike-specific T cells from convalescent vaccinees differed strikingly from those of infection-naive vaccinees, with phenotypic features suggesting superior long-term persistence and ability to home to the respiratory tract including the nasopharynx. These results provide reassurance that vaccine-elicited T cells respond robustly to emerging viral variants, confirm that convalescents may not need a second vaccine dose, and suggest that vaccinated convalescents may have more persistent nasopharynx-homing SARS-CoV-2-specific T cells compared to their infection-naive counterparts.

immunology↗

bioRxiv2021

The CCL2 Chemokine Promotes Early Seeding of the Latent HIV Reservoir

HIV infects long-lived CD4 memory T cells establishing a latent viral reservoir that necessitates lifelong anti-retroviral therapy (ART). How this reservoir is formed so swiftly remains unknown. We now show the innate inflammatory response to HIV infection results in CCL2 chemokine release, which can drive recruitment of cells expressing the CCR2 receptor including a subset of central memory CD4 T cells. Supporting a role for the CCL2/CCR2 axis in rapid reservoir formation, we find 1) treatment of humanized mice with anti-CCL2 antibodies during HIV infection decreases reservoir seeding and 2) CCR2/5+ cells from the blood of HIV-infected individuals on long term ART contain significantly more provirus than CCR2/5-negative memory or naive cells. Together, these studies support a model where the hosts innate inflammatory CCL2 response to HIV infection recruits CCR2/5+ central memory CD4 T cells to zones of virus-associated inflammation likely contributing to rapid formation of the latent HIV reservoir. GRAPHICAL ABSTRACTWhy is the latent HIV reservoir established so early following infection? An innate immune response occurs during acute infection that establishes a "zone of inflammation" (step 1). The CCL2 chemokine is produced in part through IFI16 sensing of HIV DNA in abortively infected cells. CCL2 promotes rapid recruitment of CCR2/5+ memory CD4 T cells (step 2). Many of these cells become productively infected (step 3) and a fraction become latently infected (step 4). Thus, HIV hijacks the host inflammatory response to rapidly establish the latent reservoir. In support of this model, we find HIV reservoir reduction in humanized mice treated with anti-CCL2 antibodies during early infection. Further, we find that CCR2/5+ CD4 T cells harbor a substantial fraction of detectable proviruses in the blood of HIV-infected individuals on long-term suppressive ART. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/432826v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@8d6da8org.highwire.dtl.DTLVardef@11a3a1corg.highwire.dtl.DTLVardef@dd05dborg.highwire.dtl.DTLVardef@ab84e6_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2021

Human Pre-Implantation Embryos Are Permissive to SARS-CoV-2 Entry

The spread of SARS-CoV-2 has led to a devastating pandemic, with infections resulting in a range of symptoms collectively known as COVID-19. The full repertoire of human tissues and organs susceptible to infection is an area of active investigation, and some studies have implicated the reproductive system. The effects of COVID-19 on human reproduction remain poorly understood, and particularly the impact on early embryogenesis and establishment of a pregnancy are not known. In this work, we explore the susceptibility of early human embryos to SARS-CoV-2 infection. We note that ACE2 and TMPRSS2, two canonical cell entry factors for SARS-CoV-2, are co-expressed in cells of the trophectoderm in blastocyst-stage preimplantation embryos. Using fluorescent reporter virions pseudotyped with Spike (S) glycoprotein from SARS-CoV-2, we observe robust infection of trophectoderm cells, and this permissiveness could be attenuated with blocking antibodies targeting S or ACE2. When exposing human blastocysts to the live, fully infectious SARS-CoV-2, we detected cases of infection that compromised embryo health. Therefore, we identify a new human target tissue for SARS-CoV-2 with potential medical implications for reproductive health during the COVID-19 pandemic and its aftermath.

developmental biology↗

bioRxiv2020

The Atlas of the In Vivo HIV CD4 T Cell Reservoir

ABSTRACTThe latent reservoir is a main barrier for curing HIV. But because latently-infected cells cannot be phenotyped directly, the features of the in vivo reservoir have remained elusive. Here, we describe a method that leverages high-dimensional phenotyping using CyTOF to trace latently-infected cells reactivated ex vivo to their original pre-activation states. Our results suggest that contrary to common assumptions, the reservoir is not randomly distributed among cell subsets, and is remarkably conserved between individuals. However, reservoir composition differs between tissues and blood, as do cells successfully reactivated by different latency reversing agents. Most importantly, by selecting 8-10 of our 39 original CyTOF markers, we were able to isolate highly purified populations of unstimulated in vivo latent cells, thereby validating the PP-SLIDE approach for reservoir characterization. These purified populations were highly enriched for replication-competent and intact provirus, transcribed HIV, and displayed clonal expansion. The ability to isolate unstimulated latent cells from infected individuals enables previously impossible studies of HIV persistence.Competing Interest StatementThe authors have declared no competing interest.View Full Text

immunology↗

bioRxiv2020

SARS-CoV-2-specific T cells exhibit unique features characterized by robust helper function, lack of terminal differentiation, and high proliferative potential

Convalescing COVID-19 patients mount robust T cell responses against SARS-CoV-2, suggesting an important role for T cells in viral clearance. To date, the phenotypes of SARS-CoV-2-specific T cells remain poorly defined. Using 38-parameter CyTOF, we phenotyped longitudinal specimens of SARS-CoV-2-specific CD4+ and CD8+ T cells from nine individuals who recovered from mild COVID-19. SARS-CoV-2-specific CD4+ T cells were exclusively Th1 cells, and predominantly Tcm with phenotypic features of robust helper function. SARS-CoV-2-specific CD8+ T cells were predominantly Temra cells in a state of less terminal differentiation than most Temra cells. Subsets of SARS-CoV-2-specific T cells express CD127, can homeostatically proliferate, and can persist for over two months. Our results suggest that long-lived and robust T cell immunity is generated following natural SARS-CoV-2 infection, and support an important role for SARS-CoV-2-specific T cells in host control of COVID-19.

immunology↗

bioRxiv2018

Chromatin Functional States Correlate with HIV Latency Reversal in Infected Primary CD4+ T Cells

Human immunodeficiency virus (HIV) infection cannot be cured due to a small reservoir of latently infected CD4+ T cells in treated patients. The \"shock and kill\" approach proposes to eliminate the reservoir by inducing its activation and the direct or indirect killing of infected cells. Current latency reversing agents (LRAs) do not reduce the viral reservoir in treated patients.\n\nWe use a novel dual-fluorescent HIV reporter to identify and purify latent cells, and to determine the fraction of latent cells that undergo viral reactivation after infection of primary CD4+ T cells. Unexpectedly, LRAs reactivate less than 5% of latent proviruses. Analysis of HIV integration sites from induced and non-induced latent populations reveals distinct provirus integration sites between these two populations in terms of chromatin functional states.\n\nThese findings challenge \"shock and kill\", and suggest the need of more potent LRAs in combination with immunomodulatory approaches to eradicate HIV reservoir.

microbiology↗