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Pathogens that persist in their host induce immune dysfunctions even in the absence of detectable replication. To better understand the phenotypic and functional changes that persistent infections induce in sentinel innate immune cells, we developed human PBMC-based HIV models of persistent infection. Autologous nonactivated PBMCs were cocultured with chronically infected, acutely infected, or uninfected cells and were then analyzed by unsupervised high-dimensional flow cytometry. Using this approach, we identified prevalent patterns of innate immune dysfunctions associated with persistent HIV infections that at least in part mirror immune dysfunctions observed in patients. In one or more models of chronic infection, bystander CD16+ NK cells expressing markers of activation, such as CD94, CD45RO, CD62L, CD69, CD25, and immune checkpoints PD1, Tim3, TIGIT, NKG2A and Lag3, were significantly reduced. Conversely, helper ILC subsets expressing PDL1/PDL2 were significantly enriched in chronic infection compared with either uninfected or acute infection, suggesting that chronic HIV-1 infection was associated with an inhibitory environment for bystander ILC and NK subsets. The cell-based models of persistent infection that we describe here provide versatile tools to explore the molecular mechanisms of these immune dysfunctions and unveil the contribution of innate immunity in sustaining pathogen persistence.

The increasingly frequent outbreaks of pathogenic viruses have underlined the urgent need to improve our arsenal of antivirals that can be deployed for future pandemics. Innate immunity is a powerful first line of defense against pathogens, and compounds that boost the innate response have high potential to act as broad-spectrum antivirals. Here, we harnessed localization-dependent protein-complementation assays (called Alpha Centauri) to measure the nuclear translocation of interferon regulatory factors (IRFs), thus providing a readout of innate immune activation following viral infection that is applicable to high-throughput screening of immunomodulatory molecules. As proof of concept, we screened a library of kinase inhibitors on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and identified Gilteritinib as a powerful enhancer of innate responses to viral infection. This immunostimulatory activity of Gilteritinib was found to be dependent on the AXL-IRF7 axis and results in a broad and potent antiviral activity against unrelated RNA viruses.

International audience; OBJECTIVE: The main objective of the MACOMBA (Maternity and Control of Malaria-HIV co-infection in Bangui) trial was to show that cotrimoxazole (CTX) is more effective than Sulphadoxine-Pyremethamine-IPTp (IPTp-SP) to prevent placental malaria infection (primary endpoint) among HIV-positive pregnant women with a CD4+ count ≥350 cells/mm(3) in Bangui, CAR.METHODS: MACOMBA is a multicenter, open-label randomized trial conducted in four maternity hospitals in Bangui. Between 2013 and 2017, 193 women were randomized and 112 (59 and 53 in CTX and IPTp-SP arms, respectively) were assessed for placental infection defined by microscopic parasitemia or PCR.RESULTS: Thirteen women had a placental infection: 5 in the CTX arm (1 by microscopic placental parasitemia and 4 by PCR) and 8 by PCR in the SP-IPTp (8.5% vs 15.1%, p = 0.28). The percentage of newborns with low birthweight (< 2500 g) did not differ statistically between the two arms. Self-reported compliance to CTX prophylaxis was good. There was a low overall rate of adverse events in both arms.CONCLUSION: Although our results do not allow us to conclude that CTX is more effective, drug safety and good compliance among women with this treatment favour its widespread use among HIV-infected pregnant women, as currently recommended by WHO.

As a live attenuated vaccine, yellow fever vaccine (YFV) is not routinely performed after allogeneic hematopoietic stem cell transplant (HSCT) despite it being the only efficient preventive therapy. We retrospectively identified 21 HSCT recipients immunized with YFV at a median of 39 months after HSCT and a median of 33 months after withdrawal of immunosuppression without any side effects. Eighteen evaluable patients had protective immunity after YFV. We also observed that a third of the recipients vaccinated with YFV before HSCT had persistent protective immunity after HSCT.

Summary During retroviral infection, viral capsids are subject to restriction by the cellular factor TRIM5α. Here, we show that dendritic cells (DCs) derived from human and non-human primate species lack efficient TRIM5α-mediated retroviral restriction. In DCs, endogenous TRIM5α accumulates in nuclear bodies (NB) that partly co-localize with Cajal bodies in a SUMOylation-dependent manner. Nuclear sequestration of TRIM5α allowed potent induction of type I interferon (IFN) responses during infection, mediated by sensing of reverse transcribed DNA by cGAS. Overexpression of TRIM5α or treatment with the SUMOylation inhibitor ginkgolic acid (GA) resulted in enforced cytoplasmic TRIM5α expression and restored efficient viral restriction but abrogated type I IFN production following infection. Our results suggest that there is an evolutionary trade-off specific to DCs in which restriction is minimized to maximize sensing. TRIM5α regulation via SUMOylation-dependent nuclear sequestration adds to our understanding of how restriction factors are regulated., Graphical Abstract, Highlights • Primate dendritic cells (DCs) lack efficient TRIM5α-mediated retroviral restriction • In DCs TRIM5α is sequestered in the nucleus in a SUMOylation-dependent manner • TRIM5α nuclear sequestration allows DC sensing of retroviral DNA by cGAS, Retroviruses can be efficiently blocked by a cellular restriction factor called TRIM5α. Intriguingly, TRIM5α is inactive in dendritic cells (DCs). Portilho et al. show that in DCs TRIM5α is sequestered in the nucleus in a SUMOylation-dependent manner, favoring innate sensing of retroviruses in the cytoplasm by cGAS and thus an antiviral response.

We have recently reported the development of YAP-TEAD interaction inhibitors that disrupt the YAP-TEAD complex and block proliferation of tumor cells. These compounds represent promising new treatment modalities for mesothelioma where the Hippo pathway is highly deregulated, with around 45% of MPM cases displaying a mutation of NF2 or LATS and predominantly nuclear YAP localization. MPM is an extremely aggressive disease with limited treatment options and no cure and is inherently chemoresistant, with only 50% of patients responding to the standard-of-care treatment; consequently, it has a very poor prognosis. The aim of this study was to support a multipronged approach to treat MPM. We have first established the in vitro proof of concept using siRNA experiments. Then, we have evaluated the effect of several Inventiva compounds (YAP-TEAD inhibitors) on the proliferation of a well-characterized YAP-dependent mesothelioma cell line (H2052) and on a large panel of MPM cells. We have further demonstrated the mechanism of action (MOA) of our compounds investigating the nuclear localization of YAP, the YAP-TEAD interactions, and the YAP protein expression levels in H2052 cancer cell line. To demonstrate the MOA, we have used immunofluorescence, proximity ligation assay, as well as Co-IP and Western blot experiments. Furthermore, we have examined the effect of IVA compounds in combination with the standard-of-care agent pemetrexed in a 3D spheroid model, and demonstrated the target engagement by looking at YAP-TEAD target gene expression. The effect of IVA compounds has been compared to this obtained with siRNA transfection. To assess the efficacy of pemetrexed +/- Inventiva compounds, we exposed H2052 cells to either each of the single agents or to their combination for 4 or 15 days in 2D or in 3D cultures. We used EdU incorporation assay or the measure of the spheroid area to access cell proliferation. We found a synergistic effect between YAP-TEAD inhibitors and pemetrexed, leading to a drastic inhibition of cancer cell proliferation and an increase of cytotoxicity. This suggests that YAP-TEAD inhibitors used in combination with existing chemotherapeutics could be used to attenuate multidrug resistance and resensitize chemoresistant cancer cells. We are currently exploring the effect of Inventiva compounds in H2052 mouse xenograft model. This study will be expanded to other indications and combination strategies where standard-of-care agents are ineffective and YAP is activated. Citation Format: Anne Soudé, Martine Barth, Jean-Michel Luccarini, Séverine Delaporte, Florence Chirade, Christelle Valaire, Aude Boulay, Geneviève Cheret, Marie Dorchie, Céline Estivalet, Pascale Tuya-Boustugue, Robin Tranchand, Didier Jean, Lisa Quetel, Jean-Baptiste Assié, Irena Konstantinova, Jean-Louis Junien, Pierre Broqua. Discovery of YAP-TEAD protein-protein interaction inhibitors (PPI) for treating malignant pleural mesothelioma (MPM) [abstract]. In: Proceedings of the AACR Special Conference on the Hippo Pathway: Signaling, Cancer, and Beyond; 2019 May 8-11; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(8_Suppl):Abstract nr B14.

International audience; BACKGROUND: Co-infection with malaria parasite and HIV is an emerging public health problem in tropical areas, particularly in pregnant women, and management of the concurrent effects of these two infections is challenging. Co-trimoxazole is a sulfamide preparation used to prevent opportunistic infections in HIV-infected patients, and many studies have reported that it has significant activity against malaria. As the efficacy of intermittent preventive treatment (IPT) with sulfadoxine-pyrimethamine (SP) against malaria is decreasing, co-trimoxazole might be an alternative for preventing malaria among HIV-infected populations. The aim of this study is to compare the effectiveness of SP-IPT, which is recommended for the prevention of malaria during pregnancy in the Central African Republic, with that of a daily dose of co-trimoxazole against P. falciparum infections among HIV-infected pregnant women in Bangui, the capital of the Central African Republic. METHODS/DESIGN: The MACOMBA study (MAternity and COntrol of Malaria-HIV co-infection in BAngui) is a multicentre open-label randomized clinical trial conducted at four maternity hospitals in Bangui. All HIV-infected pregnant women presenting for an antenatal clinic visit between the weeks 16 and 28 of amenorrhoea, with a CD4 count of more than 350 cells/mm3, will be eligible. All the women will provide written consent before being enrolled in the study and will then be randomly allocated to either SP-IPT (25 mg of sulfadoxine and 1.25 mg of pyrimethamine) or daily co-trimoxazole doses (960 mg per dose). The primary end-point is the placental malaria parasitaemia rate at delivery. Other main outcome measures include the number of malaria episodes during pregnancy, safety, and treatment compliance. Furthermore, the frequency of molecular resistance markers dhfr and dhps will be measured. DISCUSSION: In this trial, we seek to confirm whether co-trimoxazole is operationally suitable to replace SP-IPT in order to prevent malaria among pregnant women infected with HIV in the Central African Republic. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01746199.

Trials testing the RTS,S candidate malaria vaccine and radiation-attenuated sporozoites (RAS) have shown that protective immunity against malaria can be induced and that an effective vaccine is not out of reach. However, longer-term protection and higher protection rates are required to eradicate malaria from the endemic regions. It implies that there is still a need to explore new vaccine strategies. Lentiviral vectors are very potent at inducing strong immunological memory. However their integrative status challenges their safety profile. Eliminating the integration step obviates the risk of insertional oncogenesis. Providing they confer sterile immunity, nonintegrative lentiviral vectors (NILV) hold promise as mass pediatric vaccine by meeting high safety standards. In this study, we have assessed the protective efficacy of NILV against malaria in a robust pre-clinical model. Mice were immunized with NILV encoding Plasmodium yoelii Circumsporozoite Protein (Py CSP) and challenged with sporozoites one month later. In two independent protective efficacy studies, 50% (37.5–62.5) of the animals were fully protected (p = 0.0072 and p = 0.0008 respectively when compared to naive mice). The remaining mice with detectable parasitized red blood cells exhibited a prolonged patency and reduced parasitemia. Moreover, protection was long-lasting with 42.8% sterile protection six months after the last immunization (p = 0.0042). Post-challenge CD8+ T cells to CSP, in contrast to anti-CSP antibodies, were associated with protection (r = −0.6615 and p = 0.0004 between the frequency of IFN-g secreting specific T cells in spleen and parasitemia). However, while NILV and RAS immunizations elicited comparable immunity to CSP, only RAS conferred 100% of sterile protection. Given that a better protection can be anticipated from a multi-antigen vaccine and an optimized vector design, NILV appear as a promising malaria vaccine.