Coronavirus disease 2019 (COVID-19) has rapidly become a global pandemic and no antiviral drug or vaccine is yet available for the treatment of this disease 1-3. Several clinical studies are ongoing to evaluate the efficacy of repurposed drugs that have demonstrated antiviral efficacy in vitro. Among these candidates, hydroxychloroquine (HCQ) has been given to thousands of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-the virus that causes COVID-19-worldwide but there is no definitive evidence that HCQ is effective for treating COVID-19 4-7. Here we evaluated the antiviral activity of HCQ both in vitro and in SARS-CoV-2-infected macaques. HCQ showed antiviral activity in African green monkey kidney cells (Vero E6) but not in a model of reconstituted human airway epithelium. In macaques, we tested different treatment strategies in comparison to a placebo treatment, before and after peak viral load, alone or in combination with azithromycin (AZTH). Neither HCQ nor the combination of HCQ and AZTH showed a significant effect on viral load in any of the analysed tissues. When the drug was used as a pre-exposure prophylaxis treatment, HCQ did not confer protection against infection with SARS-CoV-2. Our findings do not support the use of HCQ, either alone or in combination with AZTH, as an antiviral drug for the treatment of COVID-19 in humans. Infection with SARS-CoV-2 is characterized by initial mild disease associated with respiratory symptoms at the peak of viral replication 1,8. In some patients, a late severe immunological syndrome occurs 6-14 days after the onset of symptoms that may require intensive care and is responsible for most of the fatalities 1-3. HCQ has well-documented in vitro activity against various viruses 4 and has emerged as an active compound against SARS-CoV-2 in different screening programmes, including a library of 1,520 Food and Drug Administration (FDA)-approved compounds 5. In Vero E6 cells, HCQ has a 50% maximal effective concentration (EC 50) 5,9,10 that varies between 0.7 and 4 μM. It may inhibit viral transport in endosomes by alkalinizing the intra-organelle compartment 10,11 and affect glycosylation, as reported for other viruses 12. The drug may also act as an immunomodulatory agent 13,14. In patients with lupus, HCQ decreases the level of inflammatory cytokines 11,15,16 , which may be relevant for the treatment of COVID-19 2. Furthermore, it has been proposed that AZTH, which displays in vitro antiviral activity against SARS-COV-2 5,17 , could potentiate the efficacy of HCQ 6. On the basis of these properties, HCQ has been considered for the treatment of COVID-19, alone or in combination with AZTH 6,7. We and others have set up non-human primate (NHP) models of SARS-CoV-2 infection 18-20. Here we used cynomolgus macaques (Macaca fascicularis) to test different treatment strategies with HCQ, alone or in combination with AZTH, before or after the peak of viral replication. We also tested HCQ administration as pre-exposure prophylaxis treatment...

Despite efficient antiretroviral therapy (ART), CD4+ T cell counts often remain low in HIV-1-infected patients. This has led to IL-7, a crucial cytokine involved in both thymopoiesis and peripheral T cell homeostasis, being suggested as an additional therapeutic strategy. We investigated whether recombinant simian IL-7-treatment enhanced the T cell renewal initiated by ART in rhesus macaques chronically infected with SIVmac251. Six macaques in the early chronic phase of SIV infection received antiretroviral treatment. Four macaques also received a 3-wk course of IL-7 injections. Viral load was unaffected by IL-7 treatment. IL-7 treatment increased the number of circulating CD4+ and CD8+ memory T cells expressing activation (HLA-DR+, CD25+) and proliferation (Ki-67+) markers. It also increased naive (CD45RAbrightCD62L+) T cell counts by peripheral proliferation and enhanced de novo thymic production. The studied parameters returned to pretreatment values by day 29 after the initiation of treatment, concomitantly to the appearance of anti-IL-7 neutralizing Abs, supporting the need for a nonimmunogenic molecule for human treatment. Thus, IL-7, which increases T cell memory and de novo renewal of naive T cells may have additional benefits in HIV-infected patients receiving ART.

Highlights d Two-component protein nanoparticles display multiple copies of the SARS-CoV-2 spike d Spike protein nanoparticles enhance cognate B cell activation in vitro d Vaccination induces potent neutralization in mice, rabbits, and cynomolgus macaques d Vaccination protects macaques against a high-dose SARS-CoV-2 challenge

The current pandemic of coronavirus disease (COVID) 2019 constitutes a global public health issue. Regarding the emerging importance of the gut-lung axis in viral respiratory infections, analysis of the gut microbiota's composition and functional activity during a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection might be instrumental in understanding and controling COVID 19. We used a nonhuman primate model (the macaque), that recapitulates mild COVID-19 symptoms, to analyze the effects of a SARS-CoV-2 infection on dynamic changes of the gut microbiota. 16S rRNA gene profiling and analysis of β diversity indicated significant changes in the composition of the gut microbiota with a peak at 10-13 days post-infection (dpi). Analysis of bacterial abundance correlation networks confirmed disruption of the bacterial community at 10-13 dpi. Some alterations in microbiota persisted after the resolution of the infection until day 26. Some changes in the relative bacterial taxon abundance associated with infectious parameters. Interestingly, the relative abundance of Acinetobacter (Proteobacteria) and some genera of the Ruminococcaceae family (Firmicutes) was positively correlated with the presence of SARS-CoV-2 in the upper respiratory tract. Targeted quantitative metabolomics indicated a drop in short-chain fatty acids (SCFAs) and changes in several bile acids and tryptophan metabolites in infected animals. The relative abundance of several taxa known to be SCFA producers (mostly from the Ruminococcaceae family) was negatively correlated with systemic inflammatory markers while the opposite correlation was seen with several members of the genus Streptococcus. Collectively, SARS-CoV-2 infection in a nonhuman primate is associated with changes in the gut microbiota's composition and functional activity.

The main failure of antiretroviral therapy is the lack of restoration of HIV-specific CD4+ T cells. IL-7, which has been shown to be a crucial cytokine for thymopoiesis, has been envisaged as an additive therapeutic strategy. However, in vitro studies suggest that IL-7 might sustain HIV replication in thymocytes and T lymphocytes. Therefore, in the present study, we evaluated the effect of IL-7 on both T cell renewal and viral load in SIVmac-infected young macaques in the absence of antiretroviral therapy. This evaluation was conducted during the asymptomatic phase in view of a potential treatment of HIV patients. We show that IL-7 induces both a central renewal and a peripheral expansion of T lymphocytes associated with cell activation. No alarming modulation of the other hemopoietic cells was observed. No increase in the viral load was shown in blood or lymph nodes. These data strengthen the rationale for the use of IL-7 as an efficient immunotherapy in AIDS.

Immunological and virological events that occur during the earliest stages of SIV infection are now considered to have a major impact on subsequent disease progression. In the present study, we demonstrate a clear correlation between progression to AIDS and the rate of in vitro CD4+ (but not CD8+) T cell death in lymph nodes. The dying CD4+ T cells were effector memory T cells, which are critical for the immune response to pathogens. However, there was no correlation between the rate of the viral replication within lymph nodes and the extent of Fas ligand-mediated death, despite the increased sensitivity of CD4+ T cells to death in response to recombinant human Fas ligand. CD4+ T cell death was caspase and apoptosis-inducing factor independent but was clearly associated with mitochondrion damage. Interestingly, higher expression levels of the active form of Bak, a proapoptotic molecule involved in mitochondrial membrane permeabilization, were observed in SIV-infected macaques progressing more rapidly to AIDS. Finally, we demonstrated that the strain of SIV we used requires CCR5 and BOB/GRP15 molecules as coreceptors and caused death of unstimulated noncycling primary CD4+ T cells. Altogether, these results demonstrate that CD4+ T cell death occurring early after SIV infection is a crucial determinant of progression to AIDS and that it is mediated by the intrinsic death pathway.

Highlights d Two-component protein nanoparticles display multiple copies of the SARS-CoV-2 spike d Spike protein nanoparticles enhance cognate B cell activation in vitro d Vaccination induces potent neutralization in mice, rabbits, and cynomolgus macaques d Vaccination protects macaques against a high-dose SARS-CoV-2 challenge

The SARS-CoV-2 pandemic has affected more than 185 million people worldwide resulting in over 4 million deaths. To contain the pandemic, there is a continued need for safe vaccines that provide durable protection at low and scalable doses and are easily delivered. Here, AAVCOVID-1, an adeno-associated viral (AAV), Spike gene-based vaccine candidate demonstrates potent immunogenicity in mouse and nonhuman primates following a single injection and confers complete protection from SARS-CoV-2 challenge in macaques. Peak neutralizing antibody titers are sustained at 1 year and complemented by functional memory T-cell responses. The AAVCOVID vector has no relevant pre-existing immunity in humans, does not elicit cross-reactivity to common AAVs used in gene therapy, and its persistence and expression wanes following injection. The single, low dose requirement, high yield manufacturability, and 1-month stability for storage at room-temperature may make this technology well-suited to support effective immunization campaigns for emerging pathogens on a global scale.