Conserved broad HIV-1 Gag-specific responses associated with low viral load and high CD4+ T cell nadir and preserved HAART regimen.

Broad human immunodeficiency virus type 1 (HIV-1) Gag-specific cellular responses can control viremia and provide slow progression to Acquired immunodeficiency syndrome (AIDS). In this study, we evaluate multiple HIV-1 Gag-specific lymphoproliferative responses and find their connection with cluster of differentiation 4 (CD4)+ T cell count and viral load from chronically HIV-1-infected patients. We further search for the correlation between multiple Gag-specific lymphoproliferative responses and changes in highly active antiretroviral therapy (HAART) regimen. We found correlation between Gag-specific responses and higher CD4+ T cells nadir and low HIV-1 viral load. Additionally, we observed that HIV-1-infected subjects did not need to change HAART regimen, when multiple Gag responses are present. We concluded that the start of HAART when CD4+ T cell nadir is the highest as possible may promote Gag-specific cellular responses conservation. Multiple Gag responses must be important to suppress HIV-1 replication. Preserved Gag-specific responses reduce HIV-1 viral load and are associated with stability of HAART regimen. Keywords: HIV-1; Gag; lymphoproliferation; viral load; HAART.

Cervids ACE2 Residues that Bind the Spike Protein can Provide Susceptibility to SARS-CoV-2.

The susceptibility of the white-tailed deer (WTD; Odocoileus virginianus) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted cervids as coronavirus reservoirs. This study aimed to evaluate the angiotensin-converting enzyme 2 (ACE2) residues which bind the spike protein of SARS-CoV-2 from 16 cervids to predict their potential susceptibility to SARS-CoV-2 infection. Eleven out of 16 species presented identical ACE2 key residues to WTD ACE2. Four cervids presented K31N, a variant associated with low SARS-CoV-2 susceptibility. Large herding of cervids with ACE2 key residues identical to that of the WTD can result in extensive reservoirs of SARS-CoV-2. Cervids as potential reservoirs could favor SARS-CoV-2 adaptation and the emergence of new coronavirus strains.

Reflection About the Ancient Emergence of HTLV-2 Infection.

During millions of years, viruses have emerged and reemerged, with imbalance of photogenicity and transmissivity overtime. This letter describes that sometimes the nomenclature is uncertain what may actually happen during retrovirus evolution nowadays. This article discusses a possibility that human T-lymphotropic virus type 2 (HTLV-2) has been processed to incorporate the human genome in the last millions of years. Persistent viruses such as human immunodeficiency virus type 1 (HIV-1), HIV-2, and human T cell lymphotropic type 2 may also have potential of endogenization instead of a cytolytic process in a long time.

Functional and tissue enrichment analyses suggest that SARS-CoV-2 infection affects host metabolism and catabolism mediated by interference on host proteins.

Infection by SARS-CoV-2, the causative agent of COVID-19, is critically connected with host metabolism. Through functional enrichment analysis, the present study aims to evaluate the biological processes involving host proteins interfered by SARS-CoV-2 to verify the potential metabolic impact of the infection. Furthermore, tissue enrichment analyses and differential gene expression of host proteins were applied to understand the interference by SARS-CoV-2 on tissue levels. Results based on functional and tissue-specific enrichment analyses, presented in this study, suggest that SARS-CoV-2, mediated interference on host proteins, can affect the metabolism and catabolism of molecular building blocks and control intracellular mechanisms, including gene expression in metabolism-related organs, to support viral demands. Thus, SARS-CoV-2 can broadly affect the host metabolism and catabolism at tissue and physiological levels contributing to a more severe disease.

Prediction of SARS-CoV-2 hosts among Brazilian mammals and new coronavirus transmission chain using evolutionary bioinformatics.

Severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 are thought to transmit to humans via wild mammals, especially bats. However, evidence for direct bat-to-human transmission is lacking. Involvement of intermediate hosts is considered a reason for SARS-CoV-2 transmission to humans and emergence of outbreak. Large biodiversity is found in tropical territories, such as Brazil. On the similar line, this study aimed to predict potential coronavirus hosts among Brazilian wild mammals based on angiotensin-converting enzyme 2 (ACE2) sequences using evolutionary bioinformatics. Cougar, maned wolf, and bush dogs were predicted as potential hosts for coronavirus. These indigenous carnivores are philogenetically closer to the known SARS-CoV/SARS-CoV-2 hosts and presented low ACE2 divergence. A new coronavirus transmission chain was developed in which white-tailed deer, a susceptible SARS-CoV-2 host, have the central position. Cougar play an important role because of its low divergent ACE2 level in deer and humans. The discovery of these potential coronavirus hosts will be useful for epidemiological surveillance and discovery of interventions that can contribute to break the transmission chain. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s44149-021-00020-w.

Molecular evolution and phylogenetic analysis of SARS-CoV-2 and hosts ACE2 protein suggest Malayan pangolin as intermediary host.

An emergence of a novel coronavirus, causative agent of COVID19, named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), occurred due to cross-species transmission. Coronaviruses are a large family of viruses able to infect a great number of hosts. Entrance of SARS-CoV-2 depends on the surface (S) protein interaction with host ACE2 protein and cleavage by TMPRSS2. ACE2 could be a species-specific barrier that interferes with bat-to-human coronavirus cross-species transmission. Molecular analysis supported bats as natural hosts for SARS-CoV and involved them in MERS-CoV origin. The genomic similarity between bat RaTG13 CoV strain and SARS-CoV-2 implicates bats in the origin of the new outbreak. Additionally, there is a hypothesis for the zoonotic transmission based on contact with Malayan pangolins by humans in Huanan seafood market in Wuhan, China. To investigate bats and pangolin as hosts in SARS-CoV-2 cross-species transmission, we perform an evolutionary analysis combining viral and host phylogenies and divergence of ACE2 and TMPRSS2 amino acid sequences between CoV hosts. Phylogeny showed SARS-like-CoV-2 strains that infected pangolin and bats are close to SARS-CoV-2. In contrast to TMPRSS2, pangolin ACE2 amino acid sequence has low evolutionary divergence compared with humans and is more divergent from bats. Comparing SARS-CoV with SARS-CoV-2 origins, pangolin has yet lower ACE2 evolutionary divergence with humans than civet-the main intermediary host of SARS-CoV. Thus, pangolin has become an opportune host to intermediates bat-to-human SARS-CoV-2 jump and entry.

Is the human T-cell lymphotropic virus type 2 in the process of endogenization into the human genome?

Human T-cell lymphotropic virus type 2 (HTLV-2) infection has been shown to be endemic among intravenous drug users in parts of North America, Europe and Southeast Asia and in a number of Amerindian populations. Despite a 65% genetic similarity and common host humoral response, the human T-cell lymphotropic viruses type 1 (HTLV-1) and 2 display different mechanisms of host interaction and capacity for disease development. While HTLV-1 pathogenicity is well documented, HTLV-2 etiology in human disease is not clearly established. From an evolutionary point of view, its introduction and integration into the germ cell chromosomes of host species could be considered as the final stage of parasitism and evasion from host immunity. The extraordinary abundance of endogenous viral sequences in all vertebrate species genomes, including the hominid family, provides evidence of this invasion. Some of these gene sequences still retain viral characteristics and the ability to replicate and hence are potentially able to elicit responses from the innate and adaptive host immunity, which could result in beneficial or pathogenic effects. Taken together, this data may indicate that HTLV-2 is more likely to progress towards endogenization as has happened to the human endogenous retroviruses millions of years ago. Thus, this intimate association (HTLV-2/human genome) may provide protection from the immune system with better adaptation and low pathogenicity.

Comparative Analysis of the Secretome and Interactome of Trypanosoma cruzi and Trypanosoma rangeli Reveals Species Specific Immune Response Modulating Proteins.

Chagas disease, a zoonosis caused by the flagellate protozoan Trypanosoma cruzi, is a chronic and systemic parasitic infection that affects ~5-7 million people worldwide, mainly in Latin America. Chagas disease is an emerging public health problem due to the lack of vaccines and effective treatments. According to recent studies, several T. cruzi secreted proteins interact with the human host during cell invasion. Moreover, some comparative studies with T. rangeli, which is non-pathogenic in humans, have been performed to identify proteins directly involved in the pathogenesis of the disease. In this study, we present an integrated analysis of canonical putative secreted proteins (PSPs) from both species. Additionally, we propose an interactome with human host and gene family clusters, and a phylogenetic inference of a selected protein. In total, we identified 322 exclusively PSPs in T. cruzi and 202 in T. rangeli. Among the PSPs identified in T. cruzi, we found several trans-sialidases, mucins, MASPs, proteins with phospholipase 2 domains (PLA2-like), and proteins with Hsp70 domains (Hsp70-like) which have been previously characterized and demonstrated to be related to T. cruzi virulence. PSPs found in T. rangeli were related to protozoan metabolism, specifically carboxylases and phosphatases. Furthermore, we also identified PSPs that may interact with the human immune system, including heat shock and MASP proteins, but in a lower number compared to T. cruzi. Interestingly, we describe a hypothetical hybrid interactome of PSPs which reveals that T. cruzi secreted molecules may be down-regulating IL-17 whilst T. rangeli may enhance the production of IL-15. These results will pave the way for a better understanding of the pathophysiology of Chagas disease and may ultimately lead to the identification of molecular targets, such as key PSPs, that could be used to minimize the health outcomes of Chagas disease by modulating the immune response triggered by T. cruzi infection.

Canine distemper virus: detection of viral RNA by Nested RT-PCR in dogs with clinical diagnosis / Vírus da cinomose canina: detecção do RNA viral pelo Nested RT-PCR em cães com diagnóstico clínico

Canine distemper virus (CDV) is a pathogen which affects dogs and causes severe disease leading to death. Dogs infected with CDV can be diagnosed by RNA detection by Nested PCR technique. The following study proposed to evaluate CDV RNA in blood, urine and saliva samples. The Nested-PCR technique was able to detect CDV RNA in different types of biologic samples. The higher number of positive results was obtained in urine samples.

vírus da cinomose canina (CDV) é um patógeno que afeta cães, causando doença grave e que pode levar a morte. Os cães infectados pelo CDV podem ser diagnosticados pela detecção do RNA utilizando-se a técnica de Nested-PCR. O presente estudo teve como objetivo avaliar o RNA do CDV no sangue, urina e saliva em cães com diagnóstico clínico de cinomose. A técnica de Nested-PCR foi capaz de detectar o RNA em diferentes tipos de amostras biológicas. Obteve-se um maior número de resultados positivos em amostras de urina.