A comparative analysis of envelope and tegument proteins of suid herpesvirus 1, bovine herpesvirus 1 and bovine herpesvirus 5

Shell disorder and the HIV vaccine mystery: lessons from the legendary Oswald Avery

The search for a human immunodeficiency virus (HIV) vaccine has spanned nearly four decades without much success. A much needed paradigm shift can be found in the abnormally high levels of intrinsic disorder in the outer shells of HIVs, the hepatitis C virus (HCV), and herpes simplex viruses (HSVs), for which successful vaccines have not been established. On the other hand, this feature (high levels of intrinsic disorder in the outer shells) is completely absent in classic viruses for which effective vaccines are found, such as the rabies virus. The motions arising from the disordered outer shell result in the inability of antibodies to bind tightly to the polysaccharides on the viral surface proteins, and, therefore, induce inadequate immune response. Experiments conducted by the legendary Avery Oswald in the 1920s form the theoretical underpinning of this new model. Failures of the vaccines based on the HIV glycoprotein Gp120 and other vaccines can be traced back to the lack of understanding of the important roles of shell disorder in a "Trojan-horse" immune evasion mechanism utilized by the virus.Communicated by Ramaswamy H. Sarma.

Zika and Flavivirus Shell Disorder: Virulence and Fetal Morbidity

Zika virus (ZIKV) was first discovered in 1947 in Africa. Since then, sporadic ZIKV infections of humans have been reported in Africa and Asia. For a long time, this virus was mostly unnoticed due to its mild symptoms and low fatality rates. However, during the 2015-2016 epidemic in Central and South America, when millions of people were infected, it was discovered that ZIKV causes microcephaly in the babies of mothers infected during pregnancy. An examination of the M and C proteins of the ZIKV shell using the disorder predictor PONDR VLXT revealed that the M protein contains relatively high disorder levels comparable only to those of the yellow fever virus (YFV). On the other hand, the disorder levels in the C protein are relatively low, which can account for the low case fatality rate (CFR) of this virus in contrast to the more virulent YFV, which is characterized by high disorder in its C protein. A larger variation was found in the percentage of intrinsic disorder (PID) in the C protein of various ZIKV strains. Strains of African lineage are characterized by higher PIDs. Using both in vivo and in vitro experiments, laboratories have also previously shown that strains of African origin have a greater potential to inflict higher fetal morbidity than do strains of Asian lineage, with dengue-2 virus (DENV-2) having the least potential. Strong correlations were found between the potential to inflict fetal morbidity and shell disorder in ZIKV (r² = 0.9) and DENV-2 (DENV-2 + ZIKV, r² = 0.8). A strong correlation between CFR and PID was also observed when ZIKV was included in an analysis of sets of shell proteins from a variety of flaviviruses (r² = 0.8). These observations have potential implications for antiviral vaccine development and for the design of cancer therapeutics in terms of developing therapeutic viruses that penetrate hard-to-reach organs.

HIV Vaccine Mystery and Viral Shell Disorder

Hundreds of billions of dollars have been spent for over three decades in the search for an effective human immunodeficiency virus (HIV) vaccine with no success. There are also at least two other sexually transmitted viruses, for which no vaccine is available, the herpes simplex virus (HSV) and the hepatitis C virus (HCV). Traditional textbook explanatory paradigm of rapid mutation of retroviruses cannot adequately address the unavailability of vaccine for many sexually transmissible viruses, since HSV and HCV are DNA and non-retroviral RNA viruses, respectively, whereas effective vaccine for the horsefly-transmitted retroviral cousin of HIV, equine infectious anemia virus (EIAV), was found in 1973. We reported earlier the highly disordered nature of proteins in outer shells of the HIV, HCV, and HSV. Such levels of disorder are completely absent among the classical viruses, such as smallpox, rabies, yellow fever, and polio viruses, for which efficient vaccines were discovered. This review analyzes the physiology and shell disorder of the various related and non-related viruses to argue that EIAV and the classical viruses need harder shells to survive during harsher conditions of non-sexual transmissions, thus making them vulnerable to antibody detection and neutralization. In contrast, the outer shell of the HIV-1 (with its preferential sexual transmission) is highly disordered, thereby allowing large scale motions of its surface glycoproteins and making it difficult for antibodies to bind to them. The theoretical underpinning of this concept is retrospectively traced to a classical 1920s experiment by the legendary scientist, Oswald Avery. This concept of viral shapeshifting has implications for improved treatment of cancer and infections via immune evasion.

Evolutionary Diversity of Suid Herpesvirus 1 Based on Ul44 Partial Sequences

OBJECTIVE

The aim of this study was to use partial Ul44 sequences (glycoprotein C) of Suid herpesvirus 1 to examine the evolution and dynamics of the virus in different periods and hosts.

METHODS

Phylogenetic trees were constructed using the software MrBayes after analysis in the software jModelTest to evaluate the best phylogenetic models. The software SplitsTree 4.0 was used to create phylogenetic networks, and the BEAST program was used to generate data on phylogeography. Replication kinetics and serum neutralization tests were applied to tree strains from different phylogenetic groups.

RESULTS

Ul44 sequences derived from domestic swine and wild swine clustered in different clades and had different selective pressures depending on the host. We found no differences in replication kinetics and serum neutralization tests in the strains tested. Data show that the evolution of herpesviruses is complex, and different genetic groups may be evolving at different rates. Ul44 is an important marker for molecular evolution and epidemiology studies, but it is not useful for biological information.

Shell disorder, immune evasion and transmission behaviors among human and animal retroviruses

This study involves measurements of percentages of intrinsic disorder (PIDs) in the GAG protein shells of various retroviruses. Unique patterns of shell protein disorder can be seen especially when GAG proteins (matrix M, capsid C, and nucleocapsid N) of primate and non-primate retroviruses are compared. HIV-1 presents the most unique pattern of disorder distribution with generally high levels of disorder in all three proteins, while EIAV (PIDs:: 26, 29, 13) is diametrically different from HIV-1 (N C M PIDs: 39.5 ± 3.0, 44.5 ± 2.6, 56.5 ± 10.8). The HTLV viruses (CPID: 32.8 ± 3.4) resemble HIV-2 (C PID: 26.6 ± 2.9) with a moderately disordered capsid. Totally distinct patterns, however, are seen for the non-primate retroviruses. They generally have highly disordered nucleocapsids (PID > 65%) and more ordered outer shells especially the matrix. These characteristics might be attributed to the differences in the way the retroviruses are transmitted, with non-primate viruses having greater non-sexual transmission components such as oral-fecal transmission. These differences are also evolutionarily related to the ways the viruses evade the host immune systems, and thus, have implications for oncolytic virotherapy and animal models in vaccine research. The importance of protein shell disorder in immune evasion, as related to the case of HIV-1, and the difficult search for its vaccines are highlighted.

Pseudorabies virus can be classified into five genotypes using partial sequences of UL44

Suid herpesvirus 1 (SuHV-1) is the causative agent of pseudorabies (PR), a disease of great importance due to the huge losses it causes in the swine industry. The aim of this study was to determine a method for genotyping SuHV-1 based on partial sequences of the gene coding for glycoprotein C (gC) and to elucidate the possible reasons for the variability of this region. A total of 109 gCsequences collected from GenBank were divided into five major groups after reconstruction of a phylogenetic tree by Bayesian inference. The analysis showed that a portion of gC (approximately 671 bp) is under selective pressure at various points that coincide with regions of protein disorder. It was also possible to divide SuHV-1 into five genotypes that evolved under different selective pressures. These genotypes are not specific to countries or continents, perhaps due to multiple introduction events related to the importation of swine.

PCR Multiplex para detecção dos principais herpesvírus neurológicos de ruminantes

Desenvolveu-se uma PCR multiplex (mPCR) para diagnóstico diferencial de encefalite bovina causada por herpesvírus suíno 1 (SuHV-1), herpesvírus bovino 1 (BoHV-1), herpesvírus bovino 5 (BoHV-5) e herpesvírus ovino 2 (OvHV-2). Os iniciadores foram projetados após alinhamento de sequências disponíveis no banco de genomas (GenBank) e a reação foi padronizada levando-se em consideração a concentração dos reagentes e os tipos diferentes de DNA polimerase. Após determinação da especificidade e sensibilidade, 65 amostras de encéfalo de bovinos com síndrome neurológica foram submetidas à análise. A sensibilidade analítica para detecção de BoHV-1, BoHV-5 e SuHV-1 foi, respectivamente, 10(1,2) TCID50/50µL, 10(1,0) TCID50/50µL, 10(1,3) TCID50/50µL na reação multiplex. Das 65 amostras analisadas, 10 foram positivas para BoHV-5, uma para BoHV-1 e cinco para OvHV-2. A mPCR descrita neste trabalho mostrou-se uma técnica útil para o diagnóstico diferencial de enfermidades relacionadas ao sistema nervoso central de bovinos.