The major histocompatibility complex (MHC) class I region of humans, chimpanzees (Pan troglodytes), and bonobos (Pan paniscus) is highly similar, and orthologues of HLA-A, -B, and -C are present in both Pan species. Based on functional characteristics, the different HLA-A allotypes are classified into different supertypes. One of them, the HLA A03 supertype, is widely distributed among different human populations. All contemporary known chimpanzee and bonobo MHC class I A allotypes cluster genetically into one of the six HLA-A families, HLA-A1/A3/A11/A30 We report here that the peptide-binding motif of the Patr-A*0501 allotype, which is commonly present in a cohort of Western-African chimpanzees, has a strong preference for binding peptides with basic amino acids at the carboxyl terminus. This phenomenon is shared with the family members of the HLA A03 supertype. Based on the chemical similarities in the peptide-binding pocket, we inferred that the preference for binding peptides with basic amino acids at thes may contribute to understand the shaping of their immune repertoire. The abundant presence of MHC-A allotypes that prefer peptides with basic amino acids at the C-terminus suggests that these molecules may contribute to the control of retroviral infections in humans, chimpanzees, and bonobos. Copyright © 2020 American Society for Microbiology.Duck Tembusu virus (DTMUV), which is similar to other mosquito-borne flaviviruses that replicate well in most mammalian cells, is an emerging pathogenic flavivirus that has caused epidemics in egg-laying and breeding waterfowl. Immune organ defects and neurological dysfunction are the main clinical symptoms of DTMUV infection. Preinfection with DTMUV makes the virus impervious to later interferon (IFN) treatment, revealing that DTMUV has evolved some strategies to defend against host IFN-dependent antiviral responses. Immune inhibition was further confirmed by screening for DTMUV-encoded proteins, which suggested that NS2A significantly inhibited IFN-β and IFN-stimulated response element (ISRE) promoter activity in a dose-dependent manner and facilitated reinfection with duck plague virus (DPV). DTMUV NS2A was able to inhibit duck RIG-I-, MDA5-, MAVS-, STING- and TBK1- induced IFN-β transcription, but not duck TBK1- and IRF7-mediated effective phases of IFN response. Furthermore, we found that NS2A competed w production and effective phases of IFN response. Uncovering the mechanism by which DTMUV NS2A inhibits IFN in the cells of its natural hosts, ducks, will help us understand the role of NS2A in DTMUV pathogenicity. Copyright © 2020 American Society for Microbiology.Influenza A (IAV) viruses cause more than two million annual episodes of seasonal acute respiratory infections (ARI) and approximately 500 thousand deaths worldwide. Depending on virus strain and host immune status, acute infections by IAV may reach sites other than the respiratory tract. In the present study, IAV virus RNA and antigens were searched for in tissues of palatine tonsils and adenoids removed from patients without ARI symptoms. A real-time RT-PCR screening revealed that 8 tissue samples from 7 patients out of 103 were positive for IAV. Positive samples were subjected to NGS and 3 of 8 tissues yielded complete IAV pH1N1 genomes, whereas in 5 samples the PB1 gene was not fully assembled. Phylogenetic analysis placed tonsil-derived IAV in clusters clearly segregated from contemporaneous Brazilian viruses. Flow cytometry of dispersed tissue fragments and serial immunohistochemistry of paraffin-embedded sections of naturally infected biopsies, indicated that CD20+ B lymphocytes, CD8+ T lymphocytes, anntemporaneous IAVs circulating in Brazil and detected in swabs and nasal washes. Inside the tissue microenvironment, immune cells were shown to be carrying IAV antigens, especially B and T CD8+ lymphocytes. Taken together, these results suggest that human lymphoid tissues can be sites of silent IAV infections with possible impact on virus shedding to the population.  https://www.selleckchem.com/products/bmh-21.html  Copyright © 2020 American Society for Microbiology.The capsid protein (Cap) is the sole structural protein and the main antigen of porcine circovirus type 2 (PCV2). Structural loops of the Cap play crucial roles in viral genome packaging, capsid assembly and virus-host interactions. Although the molecular mechanisms are yet unknown, the C-terminus (CT) of the PCV2 Cap is known to play critical roles in the evolution, pathogenesis and proliferation of this virus. In this study, we investigated functions of CT. Removal of this loop leads to abrogation of the in vitro Cap self-assembly into virus-like particles (VLPs). Likewise, the mutated virus resists rescue from PK15 cell culture. A conserved PXXP motif in the CT is dispensable for VLP assembly and subsequent cell entry. However, its removal leads to the subsequent failure of virus rescued from PK15 cells. Furthermore, substituting either the PCV1 counterpart or an AXXA for the PXXP motif still supports virus rescue from cell culture, but results in a dramatic decrease in viral titers compared to wild type. hat the CT should be considered as one of the key epitopes, recognized by neutralizing antibodies, for vaccine design and a target for drug development to prevent PCV2-associated diseases (PCVAD). Furthermore, it is important to respect the function of 227K for its role in cell entry if employing either PCV2 VLPs for nanoscale DNA/drug cell delivery or the use of PCV2 VLPs to display a variety of foreign epitopes for immunization. Copyright © 2020 American Society for Microbiology.Ascoviruses are large, enveloped DNA viruses that induce remarkable changes in cellular architecture during which the cell is partitioned into numerous vesicles for viral replication. Previous studies show these vesicles arise from a process resembling apoptosis, yet differ after nuclear lysis in that mitochondria are not degraded but are modified by the virus, changing in size, shape, and motility. Moreover, infection does not provoke an obvious innate immune response. Thus, we used in vivo RNA-sequencing to determine whether infection by the Spodoptera frugiperda ascovirus (SfAV-1a) modified expression of host mitochondrial, cytoskeletal and innate immunity genes. We show transcripts from many mitochondrial genes were similar to uninfected controls, whereas others increased slightly during vesicle formation, including those for ATP6, ATP8 synthase and NADH dehydrogenase subunits, supporting EM data that these organelles were conserved for virus replication. Transcripts from 58 of 106 cytoskeletal genes studied increased or decreased more than 2-fold post-infection.