Characterization of an Effective CTL Response against HIV and SIV Infections

A vaccine inducing protective immunity in mucosal tissues and secretions may stop or limit HIV infection. Although cytotoxic T lymphocytes (CTLs) are clearly associated with control of viral replication in HIV and simian immunodeficiency virus (SIV) infections, there are examples of uncontrolled viral replication in the face of strong CD8+ T-cell responses. The number of functions, breadth, avidity, and magnitude of CTL response are likely to be important factors in the effectiveness of anti-HIV T-cell response, but the location and persistence of effector CD8+ T cells are also critical factors. Although the only HIV vaccine clinical trial targeting cellular immunity to prevent HIV infection failed, vaccine strategies using persistent agents against pathogenic mucosal challenge in macaque models are showing unique success. Thus, the key to control the initial focus of viral replication at the portal of entry may rely on the continuous generation of effector CTL responses at mucosal level

Use of Nonhuman Primate Models to Develop Mucosal AIDS Vaccines

The HIV vaccines tested in the halted Step efficacy trial and the modestly successful phase 3 RV144 trial were designed to elicit strong systemic immune responses; therefore, strategies to direct immune responses into mucosal sites should be tested in an effort to improve AIDS vaccine efficacy. However, as increased CD4+ T-cell activation and recruitment to mucosal sites have the potential to enhance HIV transmission, mucosal immune responses to HIV vaccines should primarily consist of effector CD8+ T cells and plasma cells. Controlling the level of mucosal T-cell activation may be a critical factor in developing an effective mucosal AIDS vaccine. Immunization routes and adjuvants that can boost antiviral immunity in mucosal surfaces offer a reasonable opportunity to improve AIDS vaccine efficacy. Nonhuman primate models offer the best system for preclinical evaluation of these approaches

Infection with host-range mutant adenovirus 5 suppresses innate immunity and induces systemic CD4+ T cell activation in rhesus macaques.

Ad5 is a common cause of respiratory disease and an occasional cause of gastroenteritis and conjunctivitis, and seroconversion before adolescence is common in humans. To gain some insight into how Ad5 infection affects the immune system of rhesus macaques (RM) 18 RM were infected with a host-range mutant Ad5 (Ad5hr) by 3 mucosal inoculations. There was a delay of 2 to 6 weeks after the first inoculation before plasmacytoid dendritic cell (pDC) frequency and function increased in peripheral blood. Primary Ad5hr infection suppressed IFN-γ mRNA expression, but the second Ad5hr exposure induced a rapid increase in IFN-gamma mRNA in peripheral blood mononuclear cells (PBMC). Primary Ad5hr infection suppressed CCL20, TNF and IL-1 mRNA expression in PBMC, and subsequent virus exposures further dampened expression of these pro-inflammatory cytokines. Primary, but not secondary, Ad5hr inoculation increased the frequency of CXCR3+ CD4+ T cells in blood, while secondary, but not primary, Ad5hr infection transiently increased the frequencies of Ki67+, HLADR+ and CD95+/CCR5+ CD4+ T cells in blood. Ad5hr infection induced polyfunctional CD4 and CD8+ T cells specific for the Ad5 hexon protein in all of the animals. Thus, infection with Ad5hr induced a complex pattern of innate and adaptive immunity in RM that included transient systemic CD4+ T cell activation and suppressed innate immunity on re-exposure to the virus. The complex effects of adenovirus infection on the immune system may help to explain the unexpected results of testing Ad5 vector expressing HIV antigens in Ad5 seropositive people

Depo-Provera® Treatment Does Not Abrogate Protection from Intravenous SIV Challenge in Female Macaques Immunized with an Attenuated AIDS Virus

In a previous study, progesterone treatment of female monkeys immunized with live, attenuated SHIV89.6 abrogated the generally consistent protection from vaginal simian immunodeficiency virus (SIV) challenge. The mechanisms responsible for the loss of protection remain to be defined. The objective of the present study was to determine whether Depo-Provera administration alters protection from intravenous SIV challenge in SHIV-immunized female macaques.Two groups of female macaques were immunized with attenuated SHIV89.6 and then challenged intravenously with SIVmac239. Four weeks before challenge, one animal group was treated with Depo-Provera, a commonly used injectable contraceptive progestin. As expected, SHIV-immunized monkeys had significantly lower peak and set-point plasma viral RNA levels compared to naïve controls, but in contrast to previously published findings with vaginal SIV challenge, the Depo-Provera SHIV-immunized animals controlled SIV replication to a similar, or even slightly greater, degree than did the untreated SHIV-immunized animals. Control of viral replication from week 4 to week 20 after challenge was more consistent in the progesterone-treated, SHIV-immunized animals than in untreated, SHIV-immunized animals. Although levels of interferon-gamma production were similar, the SIV-specific CD8(+) T cells of progesterone-treated animals expressed more functions than the anti-viral CD8(+) T cells from untreated animals.Depo-Provera did not diminish the control of viral replication after intravenous SIV challenge in female macaques immunized with a live-attenuated lentivirus. This result contrasts with the previously reported effect of Depo-Provera(R) on protection from vaginal SIV challenge and strongly implies that the decreased protection from vaginal challenge is due to effects of progesterone on the genital tract rather than to systemic effects. Further, these results demonstrate that the effects of hormonal contraceptives on vaccine efficacy need to be considered in the context of testing and use of an AIDS vaccine

Dextran sulfate from Leuconostoc mesenteroides B512F exerts potent antiviral activity against SARS-CoV-2 in vitro and in vivo

SARS–CoV–2; Dextran sulfate; NebulizationSARS–CoV–2; Sulfato de dextrano; NebulizaciónSARS–CoV–2; Sulfat de dextrano; NebulitzacióThe emergent human coronavirus SARS-CoV-2 and its resistance to current drugs makes the need for new potent treatments for COVID-19 patients strongly necessary. Dextran sulfate (DS) polysaccharides have long demonstrated antiviral activity against different enveloped viruses in vitro. However, their poor bioavailability has led to their abandonment as antiviral candidates. Here, we report for the first time the broad-spectrum antiviral activity of a DS-based extrapolymeric substance produced by the lactic acid bacterium Leuconostoc mesenteroides B512F. Time of addition assays with SARS-CoV-2 pseudoviruses in in vitro models confirm the inhibitory activity of DSs in the early stages of viral infection (viral entry). In addition, this exopolysaccharide substance also reports broad-spectrum antiviral activity against several enveloped viruses such as SARS-CoV-2, HCoV229E, HSV-1, in in vitro models and in human lung tissue. The toxicity and antiviral capacity of DS from L. mesenteroides was tested in vivo in mouse models which are susceptible to SARS-CoV-2 infection. The described DS, administered by inhalation, a new route of administration for these types of polymers, shows strong inhibition of SARS-CoV-2 infection in vivo, significantly reducing animal mortality and morbidity at non-toxic doses. Therefore, we suggest that it may be considered as a potential candidate for antiviral therapy against SARS-CoV-2.Financial support for the study was provided by the REACT-EU 2021 grant from Comunidad de Madrid to the Project COVTRAVI-19-CM, Plataformas y modelos preclínicos para el abordaje multidisciplinar en COVID-19 y en respuesta a futuras pandemias

Effects of Albumin on Survival after a Hepatic Encephalopathy Episode: Randomized Double-Blind Trial and Meta-Analysis

Albúmina; Assaig clínic; MetanàlisiAlbumin; Clinical trial; Meta-analysisAlbúmina; Ensayo clínico; MetaanálisisNo therapies have been proven to increase survival after a hepatic encephalopathy (HE) episode. We hypothesize that two doses of albumin could improve 90-day survival rates after a HE episode. Methods: (1) A randomized double-blind, placebo-controlled trial (BETA) was conducted in 12 hospitals. The effect of albumin (1.5 g/kg at baseline and 1 g/kg on day 3) on 90-day survival rates after a HE episode grade II or higher was evaluated. (2) A meta-analysis of individual patient’s data for survival including two clinical trials (BETA and ALFAE) was performed. Results: In total, 82 patients were included. Albumin failed to increase the 90-day transplant-free survival (91.9% vs. 80.5%, p = 0.3). A competing risk analysis was performed, observing a 90-day cumulative incidence of death of 9% in the albumin group vs. 20% in the placebo (p = 0.1). The meta-analysis showed a benefit in the albumin group, with a lower rate of clinical events (death or liver transplant) than patients in the placebo (HR, 0.44; 95% CI, 0.21–0.82), when analyzed by a competing risk analysis (90-days mortality rate of 11% in the albumin group vs. 30% in the placebo, p = 0.02). Conclusions: Repeated doses of albumin might be beneficial for patient’s survival as an add-on therapy after an HE episode, but an adequately powered trial is needed.This work was supported by grants ICI14/00352 and PI/18/00947 from Instituto de Salud Carlos III (ISCIII) and co-funded by the European Union (ERDF/ESF, “Investing in your future”—Una manera de hacer Europa). MVC and MST are both recipients of Juan Rodes grants from ISCIII. JG is a recipient of a research intensification grant from the ISCIII. CIBERehd is supported by ISCIII. ACS is a recipient of the Rio Hortega grant from ISCIII. The work was independent of all funding

Schlafen 12 restricts HIV-1 latency reversal by a codon-usage dependent post-transcriptional block in CD4+ T cells

HIV infections; Restriction factorsInfecciones por VIH; Factores de restricciónInfeccions pel VIH; Factors de restriccióLatency is a major barrier towards virus elimination in HIV-1-infected individuals. Yet, the mechanisms that contribute to the maintenance of HIV-1 latency are incompletely understood. Here we describe the Schlafen 12 protein (SLFN12) as an HIV-1 restriction factor that establishes a post-transcriptional block in HIV-1-infected cells and thereby inhibits HIV-1 replication and virus reactivation from latently infected cells. The inhibitory activity is dependent on the HIV-1 codon usage and on the SLFN12 RNase active sites. Within HIV-1-infected individuals, SLFN12 expression in PBMCs correlated with HIV-1 plasma viral loads and proviral loads suggesting a link with the general activation of the immune system. Using an RNA FISH-Flow HIV-1 reactivation assay, we demonstrate that SLFN12 expression is enriched in infected cells positive for HIV-1 transcripts but negative for HIV-1 proteins. Thus, codon-usage dependent translation inhibition of HIV-1 proteins participates in HIV-1 latency and can restrict the amount of virus release after latency reversal.This work was supported by following grants: M.K.I., JSPS Oversea Research Fellowship and Takeda Science Foundation; A.E.C., PT17/0009/0019 (ISCIII/MINECO and FEDER); M.J.B., RTI2018-101082-B-I00 and PID2021-123321OB-I00 [MINECO/FEDER]), and the Miguel Servet program by ISCIII (CP17/00179 and CPII22/00005); C.B., M.R.R., C.D.C., European Union’s Horizon 2020 research and innovation program under grant agreement 681137-EAVI2020 and NIH grant P01-AI131568; J.D., the Spanish Ministry of Science and Innovation (PID2019106959RB-I00/AEI/10.13039/501100011033); A.M., the Spanish Ministry of Science and Innovation (PID2019-106323RB-I00 AEI//10.13039/501100011033) and the institutional “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000792-M)

Duration of the acute hepatic encephalopathy episode determines survival in cirrhotic patients

Altres ajuts: MST is a recipient of a Río Hortega grant from Instituto de Salud Carlos III, Spain. JG is a recipient of a Research Intensification grant from Instituto de Salud Carlos III, Spain. MVC is a recipient of a scholarship grant for study extension abroad, sponsored by the Spanish Association for the Study of the Liver. CIBERehd is supported by Instituto de Salud Carlos III, Spain.Episodes of hepatic encephalopathy (HE) have been related to low survival rate. However, the relation between its clinical evolution and mortality has not been assessed. A retrospective analysis of 245 cirrhotic patients admitted for an acute episode of HE (⩾grade 2) or who developed an HE episode after an upper gastrointestinal bleeding (UGIB) event was performed to assess the relation between time in HE and transplant-free survival. Median (IQR) time in HE was 48 h (24-96 h) in the whole cohort. Patients who presented a longer time in HE (>48 h; n = 89) exhibited a lower transplant-free survival at 28 days (67.2% versus 88.9%, p 48 h, when comparing patients according to baseline HE grade (2 versus ⩾3) or model for end-stage liver disease (MELD) function (⩽15 versus >15). Time in HE was also an independent risk factor for mortality at each time point, hazard ratio (HR) (95 CI%) 28 days 2.59 (1.39-4.84); 90 days 1.98 (1.28-3.1) and 365 days 1.5 (1.08-2.19). The duration of the acute HE episode determines survival in cirrhotic patients independently of liver function and baseline HE grade

Identification of HIV-reservoir cells with reduced susceptibility to antibody-dependent immune response

HIV; Infectious disease; ReservoirVIH; Malalties infeccioses; ReservoriVIH; Enfermedades infecciosas; ReservorioHuman immunodeficiency virus (HIV) establishes a persistent infection in heterogeneous cell reservoirs, which can be maintained by different mechanisms including cellular proliferation, and represent the main obstacle to curing the infection. The expression of the Fcγ receptor CD32 has been identified as a marker of the active cell reservoirs in people on antiretroviral therapy (ART), but if its expression has any role in conferring advantage for viral persistence is unknown. Here, we report that HIV-infected cells expressing CD32 have reduced susceptibility to natural killer (NK) antibody-dependent cell cytotoxicity (ADCC) by a mechanism compatible with the suboptimal binding of HIV-specific antibodies. Infected CD32 cells have increased proliferative capacity in the presence of immune complexes, and are more resistant to strategies directed to potentiate NK function. Remarkably, reactivation of the latent reservoir from antiretroviral-treated people living with HIV increases the pool of infected CD32 cells, which are largely resistant to the ADCC immune mechanism. Thus, we report the existence of reservoir cells that evade part of the NK immune response through the expression of CD32.This study was supported by the Spanish Secretariat of Science and Innovation and FEDER funds (grants SAF2015-67334-R and RTI2018-101082-B-I00 [MINECO/FEDER]), the Spanish “Ministerio de Economia y Competitividad, Instituto de Salud Carlos III” (ISCIII, PI17/01470), GeSIDA and the Spanish AIDS network Red Temática Cooperativa de Investigación en SIDA (RD16/0025/0007), the Fundació La Marató TV3 (grants 201805-10FMTV3 and 201814-10FMTV3) and the Gilead fellowships GLD19/00084 and GLD18/00008. M.B is supported by the Miguel Servet program funded by the Spanish Health Institute Carlos III (CP17/00179). A.A-G is supported by the Spanish Secretariat of Science and Innovation Ph.D. fellowship (BES-2016–076382). The funders had no role in study design, data collection, and analysis, the decision to publish, or preparation of the manuscript

KLRG1 expression on natural killer cells is associated with HIV persistence, and its targeting promotes the reduction of the viral reservoir

HIV infection; HIV reservoir; ImmunotherapyInfección por VIH; Reservorio de VIH; InmunoterapiaInfecció per VIH; Reservori de VIH; ImmunoteràpiaHuman immunodeficiency virus (HIV) infection induces immunological dysfunction, which limits the elimination of HIV-infected cells during treated infection. Identifying and targeting dysfunctional immune cells might help accelerate the purging of the persistent viral reservoir. Here, we show that chronic HIV infection increases natural killer (NK) cell populations expressing the negative immune regulator KLRG1, both in peripheral blood and lymph nodes. Antiretroviral treatment (ART) does not reestablish these functionally impaired NK populations, and the expression of KLRG1 correlates with active HIV transcription. Targeting KLRG1 with specific antibodies significantly restores the capacity of NK cells to kill HIV-infected cells, reactivates latent HIV present in CD4+ T cells co-expressing KLRG1, and reduces the intact HIV genomes in samples from ART-treated individuals. Our data support the potential use of immunotherapy against the KLRG1 receptor to impact the viral reservoir during HIV persistence.The project leading to these results has received funding from “la Caixa” Banking Foundation under the project code LCF/PR/HR20-00218. This study was also supported by the Agencia Estatal de Investigación project PID2021-123321OB-I00 funded by MCIN/AEI/10.13039/501100011033/FEDER, UE; The Spanish “Ministerio de Economia y Competitividad, Instituto de Salud Carlos III” (ISCIII, PI20/00160); and the Gilead fellowships GLD19/00084, GLD18/00008, GLD21-00049, and GLD22/00152. Part of the methodology was developed with the support of the grant 202104-30-31 from Fundació la Marató de TV3. M.B. is supported by the Miguel Servet program funded by the Spanish Health Institute Carlos III (CPII22/00005). A.A.-G. was supported by the Spanish Secretariat of Science and Innovation Ph.D. fellowship (BES-2016-076382). D.P. was supported by the VHIR Ph.D programme 2020. Spanish Secretariat of Science and Innovation Ph.D. fellowship. E.M.G. was supported by the Ramón y Cajal Program (RYC2018-024374-I) funded by the Spanish Secretariat of Science and Innovation, by the Comunidad de Madrid Talento Program (2017-T1/BMD-5396), and by the project PID2021-127899OB-I00 funded by MCIN /AEI /10.13039/501100011033/ FEDER, UE. We thank Dr. Joan Puñet from the flow cytometry core at the Vall d’Hebron Research Institute for his technical and scientific expertise. The funders had no role in study design, data collection, and analysis, the decision to publish, or preparation of the manuscript