EudraCT (2011-003243-21).

Highlights d Depletion of cyclophilin A (CypA) expression in CD4 + T cells blocks HIV-1 infection d CypA binding to the core prevents HIV-1 restriction by TRIM5a during T cell infection d Endogenously expressed TRIM5a binds to the HIV-1 core and blocks reverse transcription d Human TRIM5a binds to HIV-1 cores but not to cores bearing capsid changes A92E/G94D

BackgroundSeasonal influenza virus vaccination should be considered in all pediatric patients with rheumatic diseases. Few studies have addressed influenza vaccination safety and efficacy in this group. We aim to prospectively evaluate immunogenicity and safety of the trivalent inactivated influenza vaccine including A/H1N1, A/H3N2 and B strains in children with juvenile idiopathic arthritis (JIA) receiving biological therapy.MethodsThirty-five children diagnosed with JIA and 6 healthy siblings were included. Serum samples were collected prior to, 4-8 weeks and one year after vaccination. Microneutralization assays were used to determine neutralizing antibody titers. The type and duration of therapy were analyzed to determine its effect on vaccine response. Clinical data of the participants were collected throughout the study including severe adverse events (SAE) and adverse events following immunization (AEFI).ResultsTwenty-five patients (74.3%) received biological treatment for JIA; anti TNF-α was prescribed in 15, anti IL-1 receptor in 4 and anti IL-6 receptor therapy in 6 children. The seroprotection rate 4-8 weeks after vaccination in the JIA group was 96% for influenza A/(H1N1)pdm and influenza A/H3N2, and 88% for influenza B. No differences were found in GMT, seroprotection and seroconversion rates for the three influenza strains between the control group and patients receiving biological therapy. Furthermore, long-term seroprotection at 12 months after vaccination was similar in patients receiving either biological or non-biological treatments. No SAEs were observed.ConclusionsIn this study, influenza vaccination was safe and immunogenic in children with JIA receiving biological therapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12969-017-0190-0) contains supplementary material, which is available to authorized users.

SAMHD1 impedes infection of myeloid cells and resting T lymphocytes by retroviruses, and the enzymatic activity of the protein—dephosphorylation of deoxynucleotide triphosphates (dNTPs)—implicates enzymatic dNTP depletion in innate antiviral immunity. Here we show that the allosteric binding sites of the enzyme are plastic and can accommodate oligonucleotides in place of the allosteric activators, GTP and dNTP. SAMHD1 displays a preference for oligonucleotides containing phosphorothioate bonds in the Rp configuration located 3’ to G nucleotides (GpsN), the modification pattern that occurs in a mechanism of antiviral defense in prokaryotes. In the presence of GTP and dNTPs, binding of GpsN-containing oligonucleotides promotes formation of a distinct tetramer with mixed occupancy of the allosteric sites. Mutations that impair formation of the mixed-occupancy complex abolish the antiretroviral activity of SAMHD1, but not its ability to deplete dNTPs. The findings link nucleic acid binding to the antiretroviral activity of SAMHD1, shed light on the immunomodulatory effects of synthetic phosphorothioated oligonucleotides and raise questions about the role of nucleic acid phosphorothioation in human innate immunity.

The capsid-binding assay is an in vitro experiment used to determine whether cellular proteins interact with the HIV-1 core. In vitro assembled HIV-1 capsids recapitulate the surface of the HIV-1 core. The assay involves the incubation of in vitro assembled HIV-1 capsid-nucleocapsid (CA-NC) complexes with the protein in question. Subsequently, the mixture is spun through a sucrose cushion using an ultracentrifuge, and the pellet is analyzed for the presence of the protein in question. Although this binding assay is reliable, it is labor intensive and does not contain washing steps. Here we have developed a simpler and faster assay to measure whether a cellular protein is binding to capsid. More importantly, this novel capsid-binding assay contains washing steps. In this assay, we took advantage of the HIV-1 capsid mutant A14C/E45C protein, which is stabilized by disulfide bonds, and is resistant to washing steps. We validated the reliability and specificity of this novel assay by testing the capsid binding ability of TRIMCyp, CPSF6 and MxB with their corresponding controls. Overall, this novel assay provides a reliable and fast methodology to search for novel capsid binders.

Preventing influenza infection early after transplantation is essential, given the disease's high mortality. A multicentre prospective cohort study in adult solid organ transplant recipients (SOTR) receiving the influenza vaccine during four consecutive influenza seasons (2009-2013) was performed to assess the immunogenicity and safety of influenza vaccination in SOTR before and 6 months after transplantation. A total of 798 SOTR, 130 of them vaccinated within 6 months of transplantation and 668 of them vaccinated more than 6 months since transplantation. Seroprotection was similar in both groups: 73.1% vs. 76.5% for A/(H1N1)pdm (p 0.49), 67.5% vs. 74.1% for A/H3N2 (p 0.17) and 84.2% vs. 85.2% for influenza B (p 0.80), respectively. Geometric mean titres after vaccination did not differ among groups: 117.32 (95% confidence interval (CI) 81.52, 168.83) vs. 87.43 (95% CI 72.87, 104.91) for A/(H1N1)pdm, 120.45 (95% CI 82.17, 176.57) vs. 97.86 (95% CI 81.34, 117.44) for A/H3N2 and 143.32 (95% CI 103.46, 198.53) vs. 145.54 (95% CI 122.35, 174.24) for influenza B, respectively. After adjusting for confounding factors, time since transplantation was not associated with response to vaccination. No cases of rejection or severe adverse events were detected in patients vaccinated within the first 6 months after transplantation. In conclusion, influenza vaccination within the first 6 months after transplantation is as safe and immunogenic as vaccination thereafter. Thus, administration of the influenza vaccine can be recommended as soon as 1 month after transplantation.

The capsid (CA) protein lattice of HIV-1 and other retroviruses encases viral 1 genomic RNA and regulates steps that are essential to retroviral invasion of 2 target cells, including reverse transcription, nuclear trafficking, and integration of 3 viral cDNA into host chromosomal DNA 1 . Cyclophilin A (CypA), the first cellular 4 protein reported to bind HIV-1 CA 2 , has interacted with invading lentiviruses 5 related to HIV-1 for millions of years 3-7 . Disruption of the CA-CypA interaction 6 decreases HIV-1 infectivity in human cells 8-12 , but stimulates infectivity in non-7 human primate cells 13-15 . Genetic and biochemical data suggest that CypA 8 interaction with CA protects HIV-1 from a restriction factor in human cells 16-20 . 9 Discovery of the CA-specific restriction factor TRIM5α 21 , and of TRIM5-CypA 10 fusion genes that were independently generated at least four times in 11 phylogeny 4,5,15,22-25 , pointed to human TRIM5α as the CypA-sensitive restriction 12 factor. However, significant HIV-1 restriction by human TRIM5α 21 , let alone 13 inhibition of such activity by CypA 26 , has not been detected. Here, exploiting 14 reverse genetic tools optimized for primary human CD4 + T cells, macrophages, 15 and dendritic cells, we demonstrate that disruption of the CA-CypA interaction 16 renders HIV-1 susceptible to restriction by human TRIM5α, with the block 17 occurring before reverse transcription. Identical findings were obtained with 18 single-cycle vectors or with replication-competent HIV-1, including sexually-19 transmitted clones from sub-Saharan Africa. Endogenous TRIM5α was observed 20 to associate with virion cores as they entered the macrophage cytoplasm, but 21 only when the CA-CypA interaction was disrupted. These experiments resolve the 22 long-standing mystery of the role of CypA in HIV-1 replication by demonstrating 23 that this ubiquitous cellular protein shields HIV-1 from previously inapparent, but 24 potent inhibition, imposed by human TRIM5α. Hopefully this reinvigorates 25 development of CypA-inhibitors for treatment of HIV-1 and other CypA-dependent 26 pathogens 27-30 . 27To assess the role of TRIM5α and CypA in the primary human blood cell types 1 that serve as targets for HIV-1 infection in vivo, lentiviral vectors were optimized for titer 2 and knockdown efficiency in these cells 26,[31][32][33][34] . Human macrophages, dendritic cells, 3 and CD4 + T cells were transduced with lentivectors bearing a puromycin resistance 4 cassette and shRNAs targeting either TRIM5 or luciferase (Luc) as a control. After three 5 days of selection in puromycin, knockdown was confirmed by RT-qPCR for TRIM5 6 mRNA, and by rescue of N-MLV restriction (Extended Data Fig. 2a-c), as done 7 previously 26,31 . TRIM5 and Luc control knockdown cells were then challenged with 8 single-cycle, VSV G-pseudotyped, HIV-1-GFP reporter vectors. Three days later, the 9 percentage of GFP + cells was assessed by flow cytometry as a measure of infectivity 10

Introduction Our goal was to study whether influenza vaccination induced antibody mediated rejection in a large cohort of solid organ transplant recipients (SOTR). Methods Serum anti-Human Leukocyte Antigen (HLA) antibodies were determined using class I and class II antibody-coated latex beads (FlowPRA TM Screening Test) by flow cytometry. Anti-HLA antibody specificity was determined using the single-antigen bead flow cytometry (SAFC) assay and assignation of donor specific antibodies (DSA) was performed by virtual-crossmatch. Results We studied a cohort of 490 SOTR that received an influenza vaccination from 2009 to 2013: 110 (22.4%) received the pandemic adjuvanted vaccine, 59 (12%) within the first 6 months post-transplantation, 185 (37.7%) more than 6 months after transplantation and 136 (27.7%) received two vaccination doses. Overall, no differences of anti-HLA antibodies were found after immunization in patients that received the adjuvanted vaccine, within the first 6 months post-transplantation, or based on the type of organ transplanted. However, the second immunization dose increased the percentage of patients positive for anti-HLA class I significantly compared with patients with one dose (14.6% vs. 3.8%; P = 0.003). Patients with pre-existing antibodies before vaccination (15.7% for anti-HLA class I and 15.9% for class II) did not increase reactivity after immunization. A group of 75 (14.4%) patients developed de novo anti-HLA antibodies, however, only 5 (1.02%) of them were DSA, and none experienced allograft rejection. Only two (0.4%) patients were diagnosed with graft rejection with favorable outcomes and neither of them developed DSA. Conclusion Our results suggest that influenza vaccination is not associated with graft rejection in this cohort of SOTR.