Nanosensors based on LSPR are able to serologically differentiate dengue from Zika infections.

The Flaviviridae virus family was named after the Yellow-fever virus, and the latin term flavi means "of golden color". Dengue, caused by Dengue virus (DENV), is one of the most important infectious diseases worldwide. A sensitive and differential diagnosis is crucial for patient management, especially due to the occurrence of serological cross-reactivity to other co-circulating flaviviruses. This became particularly important with the emergence of Zika virus (ZIKV) in areas were DENV seroprevalence was already high. We developed a sensitive and specific diagnostic test based on gold nanorods (GNR) functionalized with DENV proteins as nanosensors. These were able to detect as little as one picogram of anti-DENV monoclonal antibodies and highly diluted DENV-positive human sera. The nanosensors could differentiate DENV-positive sera from other flavivirus-infected patients, including ZIKV, and were even able to distinguish which DENV serotype infected individual patients. Readouts are obtained in ELISA-plate spectrophotometers without the need of specific devices.

The Virulence of Different Vaccinia Virus Strains Is Directly Proportional to Their Ability To Downmodulate Specific Cell-Mediated Immune Compartments In Vivo.

Vaccinia virus (VACV) is a notorious virus for a number of scientific reasons; however, most of its notoriety comes from the fact that it was used as a vaccine against smallpox, being ultimately responsible for the eradication of that disease. Nonetheless, many different vaccinia virus strains have been obtained over the years; some are suitable to be used as vaccines, whereas others are virulent and unsuitable for this purpose. Interestingly, different vaccinia virus strains elicit different immune responses in vivo, and this is a direct result of the genomic differences among strains. In order to evaluate the net result of virus-encoded immune evasion strategies of vaccinia viruses, we compared antiviral immune responses in mice intranasally infected by the highly attenuated and nonreplicative MVA strain, the attenuated and replicative Lister strain, or the virulent WR strain. Overall, cell responses elicited upon WR infections are downmodulated compared to those elicited by MVA and Lister infections, especially in determined cell compartments such as macrophages/monocytes and CD4+ T cells. CD4+ T cells are not only diminished in WR-infected mice but also less activated, as evaluated by the expression of costimulatory molecules such as CD25, CD212, and CD28 and by the production of cytokines, including tumor necrosis factor alpha (TNF-α), gamma interferon (IFN-γ), interleukin-4 (IL-4), and IL-10. On the other hand, MVA infections are able to induce strong T-cell responses in mice, whereas Lister infections consistently induced responses that were intermediary between those induced by WR and MVA. Together, our results support a model in which the virulence of a VACV strain is proportional to its potential to downmodulate the host's immune responses.IMPORTANCE Vaccinia virus was used as vaccine against smallpox and was instrumental in the successful eradication of that disease. Although smallpox vaccination is no longer in place in the overall population, the use of vaccinia virus in the development of viral vector-based vaccines has become popular. Nonetheless, different vaccinia virus strains are known and induce different immune responses. To look into this, we compared immune responses triggered by mouse infections with the nonreplicative MVA strain, the attenuated Lister strain, or the virulent WR strain. We observed that the WR strain was capable of downmodulating mouse cell responses, whereas the highly attenuated MVA strain induced high levels of cell-mediated immunity. Infections by the intermediately attenuated Lister strain induced cell responses that were intermediary between those induced by WR and MVA. We propose that the virulence of a vaccinia virus strain is directly proportional to its ability to downmodulate specific compartments of antiviral cell responses.

Multi-walled carbon nanotubes functionalized with recombinant Dengue virus 3 envelope proteins induce significant and specific immune responses in mice.

BACKGROUND: Dengue is the most prevalent arthropod-borne viral disease in the world. In this article we present results on the development, characterization and immunogenic evaluation of an alternative vaccine candidate against Dengue. METHODS: The MWNT-DENV3E nanoconjugate was developed by covalent functionalization of carboxylated multi-walled carbon nanotubes (MWNT) with recombinant dengue envelope (DENV3E) proteins. The recombinant antigens were bound to the MWNT using a diimide-activated amidation process and the immunogen was characterized by TEM, AFM and Raman Spectroscopy. Furthermore, the immunogenicity of this vaccine candidate was evaluated in a murine model. RESULTS: Immunization with MWNT-DENV3E induced comparable IgG responses in relation to the immunization with non-conjugated proteins; however, the inoculation of the nanoconjugate into mice generated higher titers of neutralizing antibodies. Cell-mediated responses were also evaluated, and higher dengue-specific splenocyte proliferation was observed in cell cultures derived from mice immunized with MWNT-DENV3E when compared to animals immunized with the non-conjugated DENV3E. CONCLUSIONS: Despite the recent licensure of the CYD-TDV dengue vaccine in some countries, results from the vaccine's phase III trial have cast doubts about its overall efficacy and global applicability. While questions about the effectiveness of the CYD-TDV vaccine still lingers, it is wise to keep at hand an array of vaccine candidates, including alternative non-classical approaches like the one presented here.

Molecular epidemiology of senecavirus A associated with vesicular disease in pigs in Brazil.

Senecavirus A (SV-A) may cause vesicular disease and neonatal mortality in pigs, and was first detected in Brazil in 2015. Samples including tissues and serum from pigs with suspected vesicular diseases were collected from January to August in 2015 from farms in the states of Minas Gerais, Santa Catarina, Goiás and Rio Grande do Sul, Brazil, and tested for the presence of SV-A by reverse transcriptase PCR. All samples were negative for foot and mouth disease virus, as well as 13 other infectious agents associated with vesicular diseases in pigs. SV-A was detected by PCR in 65/265 (24.5%) specimens. A 530 base pair fragment sequenced from the VP1 protein coding region indicated a high genetic distance from SV-A in other countries, but a common origin among the Brazilian isolates.

Detection of bovine herpesvirus 5 (BoHV-5) in formalin-fixed, paraffin-embedded bovine brain by nested PCR in Colombian cattle / Detección de herpesvirus bovino 5 (BoHV-5) en cerebro incluido en parafina y fijado en formalina, por PCR anidada, en bovinos colombianos / Detecção de herpesvírus bovino 5 (BoHV-5) em cérebro incluído em parafina e fixado em formalina, pela PCR, em bovinos colombianos

Fifteen cases of viral meningoencephalitis in Colombian cattle were tested by nested PCR analysis for the detection of bovine herpesvirus 5 (BoHV-5). All fatal cases had shown severe neurological signs and had occurred following natural outbreaks of the disease. The neurological infection was histologically characterized by mild to moderate inflammatory changes in the brain and cerebellum, including meningitis, mononuclear perivascular cuffing, gliosis, haemorrhage, and the presence of Gitter cells (macrophages) accompanying large areas of malacia. No intranuclear inclusion bodies were seen in any of the cases. Results from BoHV-5 molecular extraction analyses showed there were five positive cases thus confirming the presence of the virus in Colombia.

Quince casos de meningoencefalitis viral en ganado Colombiano fueron analizados por reacción en cadena de la polimerasa (PCR anidada) para la detección del herpesvirus bovino 5 (BoHV-5). Todos los casos mostraron severos signos neurológicos antes de morir y ocurrieron como brotes naturales de la enfermedad. La infección neurológica fue caracterizada histológicamente por leves a moderados cambios inflamatorios en el cerebro y cerebelo, incluyendo meningitis, manguitos perivasculares, gliosis, hemorragia y la presencia de células Gitter (macrófagos) acompañando grandes áreas de malacia. No se encontraron cuerpos de inclusión intranucleares en ninguno de los casos. Los resultados del análisis de la extracción molecular de BoHV-5 revelaron la existencia de cinco casos positivos, lo cual confirma la presencia del virus en Colombia.

Quinze casos de meningoencefalite viral em gado bovino Colombiano foi analisado pela reação em cadeia da polimerasa (PCR) para a detecção do herpesvírus bovino 5 (BoHV-5). Todos os casos mostraram graves sinais neurológicos antes de morrer y aconteceram como surtos naturais da doença. A infecção neurológica foi caracterizada histologicamente por leves a moderados câmbios inflamatórios no cérebro e cerebelo, incluindo meningite, manguitos perivasculares, gliose, hemorragia e a presencia de células gitter (macrófagos) acompanhando grandes áreas de malacia. Não se encontraram corpos de inclusão intranucleares em nenhum dos casos. Os resultados da análise da extração molecular do BoHV-5 por PCR revelaram a existência de cinco casos positivos, os quais confirmam a presença do vírus na Colômbia.

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) inflammatory network.

HTLV-1 associated myelopathy/ tropical spastic paraparesis (HAM/TSP) is a systemic immune-mediated inflammatory disease and tissues other than nervous can be damaged, mainly ocular, rheumatic and dermatologic. Over 90% of HTLV-1-infected individuals remain lifelong asymptomatic and this retrovirus persists indefinitely in their CD4+ T-lymphocytes. The infection is maintained due to the proliferation of lymphocytes that harbor a provirus and express HTLV-1 proteins, particularly Tax, promoting an active and selective expansion of infected T cells. High proviral load is related to disease progression, which is correlated to disequilibrium between host and virus. Cytotoxic T lymphocytes are abundant and chronically activated in asymptomatic carriers and in HAM/TSP patients. The asymptomatic carriers were shown to have a high frequency of pro-inflammatory monocytes and anti-inflammatory IL-10+CD4+ and IL-10+CD8+ T-cells, as an immunoregulatory mechanism to counterbalance the monocyte-derived TNF-alpha. A putative immunomodulatory event would be the key to control their overall immunological status. In HAM/TSP, a pro-inflammatory microenvironment is the hallmark of the immunological profile. Enhanced frequency of activated CD8+ T-cells (HLA-DR+) in combination with high CD18 surface expression has been seen. In blood and cerebrospinal fluid, increased levels of Type-1 cytokines, as interferon-(IFN)-gamma, Tumor Necrosis Factor (TNF)-alpha, Interleukin (IL)-2, and pro-inflammatory IL-6, can be found. Concerning the progression, HLA polymorphisms may influence HAM/TSP and the allele HLA-A*2 has been associated with protection. The authors showed that HAM/TSP is strongly associated with a decreased percentage of B-cells, with enhanced T/B-cell ratio and activated CD8+ T-cells. These immunological parameters have been proposed as a prognostic biomarker for HAM/TSP.

Genotyping of Chlamydia trachomatis from endocervical specimens in Brazil.

BACKGROUND: There is no data concerning genotyping of Chlamydia trachomatis from Brazilian samples. GOAL: To characterize the genotype of C. trachomatis detected in women assisted at a STD public clinic and establish the prevalence of this infection in that population. STUDY DESIGN: Endocervical samples of a group of 100 women were tested for chlamydial infection with PCR directed to C. trachomatis cryptic plasmid. Genotyping of positive samples were done after omp1 amplification and sequencing. RESULTS: The overall prevalence of C. trachomatis infection was 19%, with the highest prevalence in women between 15 and 25 years old (68.4%). Four genotypes were found associated with endocervical infections: D, E, F, and K. Sequence analysis revealed a coinfection of genotypes D and E in 1 woman. CONCLUSIONS: To our knowledge this is the first study to characterize Brazilian C. trachomatis endocervical samples and Brazilian C. trachomatis genotype coinfection. Our results also emphasize the importance of routine diagnosis of C. trachomatis for the control of this STD.