Mapping genetic determinants of the cell-culture growth phenotype of enterovirus 71

Enterovirus 71 (EV71) is a member of the species Human enterovirus A within the family Picornaviridae and is a major causative agent of epidemics of hand, foot and mouth disease associated with severe neurological disease. Three EV71 genogroups, designated A, B and C, have been identified, with 75–84 % nucleotide sequence similarity between them. Two strains, EV71-26M (genogroup B) and EV71-6F (genogroup C), were found to have distinct cell-culture growth (26M, rapid; 6F, slow) and plaque-formation (26M, large; 6F, small) phenotypes. To identify the genome regions responsible for the growth phenotypes of the two strains, a series of chimeric viruses was constructed by exchanging the 5′ untranslated region (UTR), P1 structural protein or P2/P3 non-structural protein gene regions plus the 3′UTR using infectious cDNA clones of both virus strains. Analysis of reciprocal virus chimeras revealed that the 5′UTRs of both strains were compatible, but not responsible for the observed phenotypes. Introduction of the EV71-6F P1 region into the EV71-26M clone resulted in a small-plaque and slow-growth phenotype similar to that of EV71-6F, whereas the reciprocal chimera displayed intermediate-growth and intermediate-sized plaque phenotypes. Introduction of the EV71-26M P2–P3–3′UTR regions into the EV71-6F clone resulted in a large-plaque and rapid-growth phenotype identical to that of strain EV71-26M, whereas the reciprocal chimera retained the background strain large-plaque phenotype. These results indicate that, although both the P1 and P2–P3–3′UTR genome regions influence the EV71 growth phenotype in cell culture, phenotype expression is dependent on specific genome-segment combinations and is not reciprocal

Novel marker for recombination in the 3'-untranslated region of members of the species Human enterovirus A

Human enterovirus A (HEV-A) is a species in the genus Enterovirus. Viruses belonging to this species are often responsible for hand, foot and mouth disease and associated acute neurological disease. Studies of the 3′ untranslated region (UTR) of human enterovirus 71 (HEV71) revealed a possible role in virus replication. We compared the 3′-UTRs of all members of HEV-A and confirmed the presence of a secondary structure comprising three stem-loop domains (SLDs). SLD-Z is situated closest to the stop codon and has been shown previously to affect plaque morphology. The prototype strains of coxsackieviruses A4 (CVA4), CVA14, and CVA16 carried the longer group I SLD-Z, whilst other CVAs and HEV71 carried the shorter group II SLD-Z. We demonstrate the importance of SLD-Z as a marker for the emergence of newer strains of HEV71 and CVA16 through inter-typic recombination and propose that SLD-Z is a novel evolutionary marker for recombination in HEV-A

Investigation of occult hepatitis B virus infection in anti-hbc positive patients from a liver clinic.

Occult hepatitis B infection (OBI) is manifested by presence of very low levels (<200IU/mL) of Hepatitis B viral DNA (HBV DNA) in the blood and the liver while exhibiting undetectable HBV surface antigen (HBsAg). The molecular mechanisms underlying this occurrence are still not completely understood. This study investigated the prevalence of OBI in a high-risk Australian population and compared the HBV S gene sequences of our cohort with reference sequences. Serum from HBV DNA positive, HBsAg negative, and hepatitis B core antibody (anti-HBc) positive patients (study cohort) were obtained from samples tested at SEALS Serology Laboratory using the Abbott Architect, as part of screening and diagnostic testing. From a total of 228,108 samples reviewed, 1,451 patients were tested for all three OBI markers. Only 10 patients (0.69%) out of the 1,451 patients were found to fit the selection criteria for OBI. Sequence analysis of the HBV S gene from 5 suspected OBI infected patients showed increased sequence variability in the 'a' epitope of the major hydrophilic region compared to reference sequences. In addition, a total of eight consistent nucleotide substitutions resulting in seven amino acid changes were observed, and three patients had truncated S gene sequence. These mutations appeared to be stable and may result in alterations in HBsAg conformation. These may negatively impact the affinity of hepatitis B surface antibody (anti-HBs) and may explain the false negative results in serological HBV diagnosis. These changes may also enable the virus to persist in the liver by evading immune surveillance. Further studies on a bigger cohort are required to determine whether these amino acid variations have been acquired in the process of immune escape and serve as markers of OBI

Specific activation of human interleukin-5 depends on de Novo synthesis of an AP-1 complex

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

GATA-3 Has Dual Regulatory Functions in Human Interleukin-5 Transcription

Interleukin-5 (IL-5) is a T-cell cytokine involved in Type 2 diseases and is commonly described as being coordinately regulated with other Type 2 cytokines, such as IL-4 and IL-13. Considering the unique control of eosinophilia by IL-5, such coordinate regulation would be surprising. In fact, the biological specificity of eosinophilia and its control by IL-5 suggests a unique and independent control of IL-5 regulation. In this report we show the binding of GATA-3 to three sites in the human IL-5 promoter in the human T-cell line PER117. The previously identified -70 site and another site at position - 152 are shown to positively regulate IL-5 transcription. More importantly, the site located at -400 acts as a powerful repressor of IL-5 transcription with mutagenesis of this site allowing a high level expression of IL-5 without the activation of other factors normally required for IL-5 expression. Whereas GATA-3 has been proposed to be involved in the regulation of the IL-4/IL-5/ IL-13 locus, we show here that it has another function in controlling IL-5 transcription that supports the observed unique biological function of this cytokine.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

HBV infection related tests conducted by SEALS from the January 1^st 2007 – March 15^th 2013.

<p>From January 2007 until March 2013, SEALS at POWH conducted 228, 108 tests that were related to HBV infection. Of the 105, 694 samples tested of HBsAg, 81,709 were negative while 21,985 tested positive. There were 5,568 HBeAg samples tested. Nine hundred seventy-five samples were HBeAg positive while 4,593 were HBeAg negative. Additionally, out of the 5,555 anti-HBe tests, 2,447 samples were positive and 3,108 were negative. Of the 78,089 samples tested for anti-HBc, 64,699 were negative while 13,390 samples were positive. Lastly, 4,303 out of 33,202 samples tested for HBV DNA were positive. From these tests, 23 patients were possible OBI. However, only 10 patients were in compliance with the study criteria (HBsAg negativity, HBV DNA and anti-HBc positivity) that comprised out study cohort.</p

Amino acid sequence alignment of the HBV small S protein.

<p>The numbers on the right indicate the amino acid position. The common substitutions identified in this study are shown in closed boxes. The “a” epitope is shown in dashed box. Asterisks indicate known genotype- or subtype-related variability. ‘-’ Indicates stop codon. Local references were samples obtained from SEALS at POWH dating from January 2007 until March 2013 with a serological profile of HBsAg positive, anti-HBc positive and HBV DNA positive.</p

Patient List with related serological and molecular test results.

<p>Patient List with related serological and molecular test results.</p

Nucleotide substitutions in the HBV S gene of OBI cohort with corresponding amino acid changes in the small S protein and polymerase.

<p>Nucleotide substitutions in the HBV S gene of OBI cohort with corresponding amino acid changes in the small S protein and polymerase.</p