Anti-brain protein autoantibodies are detectable in extraparenchymal but not parenchymal neurocysticercosis

Neurocysticercosis (NC) presents a spectrum of clinical manifestations, with two broad clinical entities based on the central nervous system location of the parasite: extraparenchymal (EP-NC) and parenchymal (P-NC). In this work, using quantitative immunoblot methodology, we demonstrate the presence of autoantibodies to brain proteins in CSF from EP-NC, but not P-NC, patients. There was striking correlation between the level of autoantibodies and the levels of the secreted metacestode glycoprotein HP-10, suggesting that the level of stimulation of the autoantibody response may be a function of the number of viable parasites. Nine corresponding proteins autoantigens were provisionally identified by mass spectroscopy. © 2020 Elsevier B.V.Neurocysticercosis (NC) presents a spectrum of clinical manifestations, with two broad clinical entities based on the central nervous system location of the parasite: extraparenchymal (EP-NC) and parenchymal (P-NC). In this work, using quantitative immunoblot methodology, we demonstrate the presence of autoantibodies to brain proteins in CSF from EP-NC, but not P-NC, patients. There was striking correlation between the level of autoantibodies and the levels of the secreted metacestode glycoprotein HP-10, suggesting that the level of stimulation of the autoantibody response may be a function of the number of viable parasites. Nine corresponding proteins autoantigens were provisionally identified by mass spectroscopy. © 2020 Elsevier B.V

Crystal structure of a poxvirus-like zalpha domain from cyprinid herpesvirus 3

Zalpha domains are a subfamily of the winged helix-turn-helix domains sharing the unique ability to recognize CpG repeats in the left-handed Z-DNA conformation. In vertebrates, domains of this family are found exclusively in proteins that detect foreign nucleic acids and activate components of the antiviral interferon response. Moreover, poxviruses encode the Zalpha domain-containing protein E3L, a well-studied and potent inhibitor of interferon response. Here we describe a herpesvirus Zalpha-domain-containing protein (ORF112) from cyprinid herpesvirus 3. We demonstrate that ORF112 also binds CpG repeats in the left-handed conformation, and moreover, its structure at 1.75 Å reveals the Zalpha fold found in ADAR1, DAI, PKZ, and E3L. Unlike other Zalpha domains, however, ORF112 forms a dimer through a unique domain-swapping mechanism. Thus, ORF112 may be considered a new member of the Z-domain family having DNA binding properties similar to those of the poxvirus E3L inhibitor of interferon response.FCT PhD fellowships: (SFRH/BPD/71629/2010, SFRH/BD/51626/2011), MX-1428 BAG program

Expression of aberrant forms of CD22 on B lymphocytes in Cd22a lupus-prone mice affects ligand binding

CD22 functions primarily as a negative regulator of B-cell receptor signaling. The Cd22a allele has been proposed as a candidate allele for murine systemic lupus erythematosus. In this study, we explored the possible expression of aberrant forms of CD22, which differ in the N-terminal sequences constituting the ligand-binding site due to synthesis of abnormally processed Cd22 mRNA, in several Cd22a mouse strains, including C57BL/6 Cd22 congenic mice. The staining pattern of splenic B cells obtained with CY34 anti-CD22 mAb, which was expected to bind poorly to the aberrant CD22, was more heterogeneous in Cd22a mice than in Cd22b mice. Moreover, CD22 detected on B cells of Cd22a mice was expressed more weakly and as a smaller-sized protein, compared with Cd22b mice. Significantly, analysis with a synthetic CD22 ligand demonstrated that Cd22a mice carried a larger proportion of CD22 that was not bound by cis ligands on the B-cell surface than Cd22b mice. Finally, the study of C57BL/6 Cd22 congenic mice revealed that Cd22a B cells displayed a phenotype reminiscent of constitutively activated B cells (reduced surface IgM expression and augmented MHC class II expression), as reported for B cells expressing a mutant CD22 lacking the ligand-binding domain. Our demonstration that Cd22a B cells express aberrant forms of CD22, which can potentially deregulate B-cell signaling because of their decreased ligand-binding capacity, provides further support for Cd22a as a potential candidate allele for murine systemic lupus erythematosu

Human cytomegalovirus gene UL76 induces IL-8 expression through activation of the DNA damage response.

Human cytomegalovirus (HCMV), a β-herpesvirus, has evolved many strategies to subvert both innate and adaptive host immunity in order to ensure its survival and propagation within the host. Induction of IL-8 is particularly important during HCMV infection as neutrophils, primarily attracted by IL-8, play a key role in virus dissemination. Moreover, IL-8 has a positive effect in the replication of HCMV. This work has identified an HCMV gene (UL76), with the relevant property of inducing IL-8 expression at both transcriptional and protein levels. Up-regulation of IL-8 by UL76 results from activation of the NF-kB pathway as inhibition of both IKK-β activity or degradation of Ikβα abolishes the IL-8 induction and, concomitantly, expression of UL76 is associated with the translocation of p65 to the nucleus where it binds to the IL-8 promoter. Furthermore, the UL76-mediated induction of IL-8 requires ATM and is correlated with the phosphorylation of NEMO on serine 85, indicating that UL76 activates NF-kB pathway by the DNA Damage response, similar to the impact of genotoxic drugs. More importantly, a UL76 deletion mutant virus was significantly less efficient in stimulating IL-8 production than the wild type virus. In addition, there was a significant reduction of IL-8 secretion when ATM -/- cells were infected with wild type HCMV, thus, indicating that ATM is also involved in the induction of IL-8 by HCMV. In conclusion, we demonstrate that expression of UL76 gene induces IL-8 expression as a result of the DNA damage response and that both UL76 and ATM have a role in the mechanism of IL-8 induction during HCMV infection. Hence, this work characterizes a new role of the activation of DNA Damage response in the context of host-pathogen interactions

An IκB homolog encoded by African swine fever virus provides a novel mechanism for downregulation of proinflammatory cytokine responses in host macrophages

Cytokines stimulate inflammatory defenses against viral infections. In order to evade host defenses, viruses have developed strategies to counteract antiviral cytokines. African swine fever virus (ASFV) is a large, double- stranded DNA virus that infects macrophages. This study demonstrates that ASFV effectively inhibited phorbol myristic acid-induced synthesis of antiviral, proinflammatory cytokines alpha interferon, tumor necrosis factor alpha, and interleukin-8 in infected macrophages as assessed by enzyme- linked immunosorbent assay and reverse transcriptase PCR. In contrast, levels of mRNA and protein for transforming growth factor β, an anti-inflammatory cytokine, were increased by ASFV infection, suggesting that ASFV-induced inhibition of cytokine synthesis may be limited to cytokines activated by NFκB. An interleukin-8 promoter, containing an NFκB enhancer site, driving expression of a luciferase reporter gene was used to show that NFκB- dependent transcription was inhibited by the virus and by a cloned ASFV gene, A238L. This gene encodes a protein with homology to IκB, the inhibitor of NFκB. Electrophoretic mobility shift assay showed that cells expressing the A238L gene inhibited NFκB binding to DNA. These results suggest that the A238L gene product interacts with NFκB to prevent transcription and downregulate proinflammatory cytokine production. This novel viral evasion strategy encoded in a single IκB-like protein may be capable of inhibiting most macrophage NFκB-dependent antiviral mechanisms and may provide insights into how ASFV causes a fatal hemorrhagic disease of domestic pigs and a persistent infection in the African warthog, which is its natural permissive host

Recognition of foot-and-mouth disease virus and its capsid protein VP1 by bovine peripheral T lymphocytes

The role of T cells in immunity to foot-and-mouth disease virus is still poorly defined compared to that of the humoral response. In this paper we describe a systematic, longitudinal study on the cellular recognition of FMDV and its subunit protein VP1 by bovine peripheral blood T lymphocytes. Multiple vaccination with a single virus serotype induced a serotype cross-reactive proliferative T cell repertoire that varied in magnitude between individual animals and with the serotype of the vaccine used. Primary proliferative T cell responses of vaccinated and acutely infected cattle were weak relative to the magnitude of responses determined for the same animals after boosting. In contrast, the level of circulating antibody produced after both primary and secondary exposure to virus was good. Phenotypic analysis of lymphocytes from vaccinated or infected cattle showed a small increase in CD8+ T cells after infection compared to vaccination. However, in general the profiles of circulating lymphocytes elicited were similar. Thus, we were not able to use proliferative or phenotypic analyses to distinguish between vaccinated and convalescent cattle. T cell recognition of VP1 by multiply-vaccinated cattle was serotype-specific implying that the cross-reactive responses observed with whole virus may be attributed to proteins other than VP1. In contrast to other studies, immunization with recombinant VP1 induced only low levels of neutralizing antibody and failed to elicit profound proliferative responses or protection even after two immunizations.</p