Comparison of risk factors for SARS-CoV-2 infection among healthcare workers during Omicron and Delta dominance periods in Japan.

BACKGROUND: The risk factors for coronavirus disease (COVID-19) among healthcare workers (HCWs) might have changed since the emergence of the highly immune evasive Omicron variant. AIM: To compare the risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among HCWs during the Delta- and Omicron-predominant periods. METHODS: Using data from repeated serosurveys among the staff of a medical research centre in Tokyo, two cohorts were established: Delta period cohort (N = 858) and Omicron period cohort (N = 652). The potential risk factors were assessed using a questionnaire. Acute/current or past SARS-CoV-2 infection was identified by polymerase chain reaction or anti-nucleocapsid antibody tests, respectively. Poisson regression was used to calculate the risk ratio (RR) of infection risk. FINDINGS: The risk of SARS-CoV-2 infection during the early Omicron-predominant period was 3.4-fold higher than during the Delta-predominant period. Neither working in a COVID-19-related department nor having a higher degree of occupational exposure to SARS-CoV-2 was associated with an increased infection risk during both periods. During the Omicron-predominant period, infection risk was higher among those who spent ≥30 min in closed spaces, crowded spaces, and close-contact settings without wearing mask (≥3 times versus never: RR: 6.62; 95% confidence interval: 3.01-14.58), whereas no such association was found during the Delta period. CONCLUSION: Occupational exposure to COVID-19-related work was not associated with the risk of SARS-CoV-2 infection in the Delta or Omicron period, whereas high-risk behaviours were associated with an increased infection risk during the Omicron period.

Week 96 results of the randomized, multicentre Maraviroc Switch (MARCH) study.

OBJECTIVES: The Maraviroc Switch (MARCH) study week 48 data demonstrated that maraviroc, a chemokine receptor-5 (CCR5) inhibitor, was a safe and effective switch for the ritonavir-boosted protease inhibitor (PI/r) component of a two nucleos(t)ide reverse transcriptase inhibitor [N(t)RTI] plus PI/r-based antiretroviral regimen in patients with R5-tropic virus. Here we report the durability of this finding. METHODS: MARCH, an international, multicentre, randomized, 96-week open-label switch study, enrolled HIV-1-infected adults with R5-tropic virus who were stable (> 24 weeks) and virologically suppressed [plasma viral load (pVL) < 50 HIV-1 RNA copies/mL]. Participants were randomized to continue their current PI/r-based regimen (PI/r) or to switch to MVC plus two N(t)RTIs (MVC) (1:2 randomization). The primary endpoint was the difference in the proportion with pVL < 200 copies/mL at 96 weeks. The switch arm was defined as noninferior if the lower limit of the 95% confidence interval (CI) for the difference was < -12% in the intention-to-treat (ITT) population. Safety endpoints (the difference in the mean change from baseline or a comparison of proportions) were analysed as key secondary endpoints. RESULTS: Eighty-two (PI/r) and 156 (MVC) participants were randomized and included in the ITT analysis; 71 (87%) and 130 (83%) were in follow-up and on therapy at week 96. At week 96, 89.0% and 90.4% in the PI/r and MVC arms, respectively, had pVL < 50 copies/mL (95% CI -6.6, 10.2). Moreover, in those switching away from PI/r, there were significant reductions in mean total cholesterol (differences 0.31 mmol/L; P = 0.02) and triglycerides (difference 0.44 mmol/L; P < 0.001). Changes in CD4 T-cell count, renal function, and serious and nonserious adverse events were similar in the two arms. CONCLUSIONS: MVC as a switch for a PI/r is safe and effective at maintaining virological suppression while having significant lipid benefits over 96 weeks.

Recognition profiles of microsporidian Encephalitozoon cuniculi polar tube protein 1 with human immunoglobulin M antibodies.

Microsporidian Encephalitozoon cuniculi has a unique organelle called a polar tube (PT), the extrusion of which is absolutely required to invade a host cell. We recently detected anti-E. cuniculi PT immunoglobulin (Ig) M antibodies in sera from many healthy individuals. The present one-dimensional (1-D) immunoblot analysis predominantly detected a band at 52 kDa in all of the examined human sera with anti-PT IgM. The use of mouse monoclonal antibody confirmed that the 52-kDa band detected in 1-D immunoblots was an antigen derived from the PT, which represents a glycoprotein nature. In addition, from changes in the immunoreactivity of the 52-kDa band before and after treatment with NaOH, we determined that the 24 human serum samples with anti-PT IgM activities could be roughly grouped into three types: (i) sera containing antibodies against only a saccharic determinant (n=3); (ii) sera containing antibodies against only a proteinic determinant (n=11); and (iii) sera showing dual recognition of saccharic and proteinic determinants (n=10). Further two-dimensional (2-D) immunoblot analysis followed by proteomic analysis confirmed that human sera with anti-PT IgM reacted with E. cuniculi polar tube protein 1 (PTP1). Such circulating IgM antibodies may be important in the first line of defence against E. cuniculi infection.

Bayesian network analysis of resistance pathways against HIV-1 protease inhibitors.

Interpretation of Human Immunodeficiency Virus 1 (HIV-1) genotypic drug resistance is still a major challenge in the follow-up of antiviral therapy in infected patients. Because of the high degree of HIV-1 natural variation, complex interactions and stochastic behaviour of evolution, the role of resistance mutations is in many cases not well understood. Using Bayesian network learning of HIV-1 sequence data from diverse subtypes (A, B, C, F and G), we could determine the specific role of many resistance mutations against the protease inhibitors (PIs) nelfinavir (NFV), indinavir (IDV), and saquinavir (SQV). Such networks visualize relationships between treatment, selection of resistance mutations and presence of polymorphisms in a graphical way. The analysis identified 30N, 88S, and 90M for nelfinavir, 90M for saquinavir, and 82A/T and 46I/L for indinavir as most probable major resistance mutations. Moreover we found striking similarities for the role of many mutations against all of these drugs. For example, for all three inhibitors, we found that the novel mutation 89I was minor and associated with mutations at positions 90 and 71. Bayesian network learning provides an autonomous method to gain insight in the role of resistance mutations and the influence of HIV-1 natural variation. We successfully applied the method to three protease inhibitors. The analysis shows differences with current knowledge especially concerning resistance development in several non-B subtypes.

Studies on the most efficient vector systems for gene transduction into dendritic cells.

Specialized antigen-presenting cells (APC), known as dendritic cells (DC), play a pivotal role in initiating primary immune responses. Several vector systems, including adenoviral vectors, retroviral vectors, hemagglutinating virus of Japan-related vectors, and the electroporation, have been shown to transduce genes into mouse and human but not rat DC. However, there is no direct evidence to support the view that the currently used vector systems are able to transduce genes into mature DC. Inasmuch as most, if not all, gene transfer studies investigating DC or DC-related cell populations are performed employing heterogeneous-groups of cells, it is therefore important to determine the extent to which gene transduction occurs in bona fide DC. In this study, we provide evidence that none of these vector systems are able to transfer genes into mature rat DC, which are derived from bone marrow cells (BMC), driven by Flt3/Flk2 ligand and IL-6, and purified with CD161a. Nevertheless, the most efficient gene transduction was observed with developing DC progenitor cells during long-term culture of rat BMC. Successful gene transfer was achieved after 2-week culture with an HIV-based lentiviral vector system.

Molecular cloning and characterization of the gene coding for azoreductase from Bacillus sp. OY1-2 isolated from soil.

Azo dyes are regarded as pollutants because they are not readily reduced under aerobic conditions. Bacillus sp. OY1-2 transforms azo dyes into colorless compounds, and this reduction is mediated by a reductase activity for the azo group in the presence of NADPH. A 1.2-kbp EcoRI fragment containing the gene that encodes azoreductase was cloned by screening the genomic library of Bacillus sp. OY1-2 with digoxigenin-labeled probe designed from the N-terminal amino acid sequence of the purified enzyme. An open reading frame encoding the azoreductase, consisting of 178 amino acids, was predicted from the nucleotide sequence. In addition, because only a Bacillus subtillis hypothetical protein was discovered in the public databases (with an amino acid identity of 52.8%), the gene encoding the azoreductase cloned in this study was predicted to be a member of a novel family of reductases. Southern blot analysis revealed that the azoreductase gene exists as a single copy gene on a chromosome. Escherichia coli-expressing recombinant azoreductase gave a ten times greater reducing activity toward azo dyes than the original Bacillus sp. OY1-2. In addition, the expressed azoreductase purified from the recombinant E. coli lysate by Red-Sepharose affinity chromatography showed a similar activity and specificity as the native enzyme. This is the first report describing the sequencing and characterization of a gene encoding the azo dye-reducing enzyme, azoreductase, from aerobic bacteria and its expression in E. coli.

Immunogenicity and protective efficacy of oligomeric human immunodeficiency virus type 1 gp140.

The biologically active form of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein is oligomeric. We previously described a soluble HIV-1 IIIB Env protein, gp140, with a stable oligomeric structure composed of uncleaved gp120 linked to the ectodomain of gp41 (P. L. Earl, C. C. Broder, D. Long, S. A. Lee, J. Peterson, S. Chakrabarti, R. W. Doms, and B. Moss, J. Virol. 68:3015-3026, 1994). Here we compared the antibody responses of rabbits to gp120 and gp140 that had been produced and purified in an identical manner. The gp140 antisera exhibited enhanced cross-reactivity with heterologous Env proteins as well as greater neutralization of HIV-1 compared to the gp120 antisera. To examine both immunogenicity and protective efficacy, we immunized rhesus macaques with oligomeric gp140. Strong neutralizing antibodies against a homologous virus and modest neutralization of heterologous laboratory-adapted isolates were elicited. No neutralization of primary isolates was observed. However, a substantial fraction of the neutralizing activity could not be blocked by a V3 loop peptide. After intravenous challenge with simian-HIV virus SHIV-HXB2, three of the four vaccinated macaques exhibited no evidence of virus replication.

Suppression of furylfuramide-induced SOS response by acetophenones using Salmonella typhimurium TA1535/pSK1002 umu test.

The recently isolated paeonol (2-hydroxy-4-methoxyacetophenone), as one of the antimutagenic compounds from Discorea japonica, was used as a lead compound for detailed structure-activity relationship studies. Nine acetophenones (2-hydroxy-4-methoxy, 2-hydroxy-5-methoxy, 2-hydroxy-6-methoxy, 4-hydroxy-3-methoxy, o-methoxy, m-methoxy, p-methoxy, and 2,5-dimethoxyacetophenone and acetophenone) were investigated for their ability of suppression of furylfuramide-induced SOS response using Salmonella typhimurium TA1535/pSK1002 in the umu test, against the mutagen, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The results showed that 2-hydroxy-6-methoxyacetophenone displayed the strongest activity (EC(50) = 0.6 micromol/mL), and a hydroxyl group at C-2 is necessary feature for acetophenone derivatives to show the suppressive effects of furylfuramide-induced SOS response.

Polymorphism in the interleukin-4 promoter affects acquisition of human immunodeficiency virus type 1 syncytium-inducing phenotype.

The emergence of syncytium-inducing (SI) variants of human immunodeficiency virus type 1 (HIV-1) in infected individuals is an indicator of poor prognosis and is often correlated with faster CD4(+) cell depletion and rapid disease progression. Interleukin-4 (IL-4) is a pleiotropic cytokine with various immune-modulating functions including induction of immunoglobulin E (IgE) production in B cells, down-regulation of CCR5 (a coreceptor for HIV-1 non-SI [NSI] strains), and up-regulation of CXCR4 (a coreceptor for HIV-1 SI variants). Here we show that homozygosity of a polymorphism in the IL-4 promoter region, IL-4 -589T, is correlated with increased rates of SI variant acquisition in HIV-1-infected individuals in Japan. This mutation was also shown to be associated with elevated serum IgE levels in HIV-1-infected individuals, especially in those at advanced stages of disease. In contrast, neither a triallele polymorphism in IL-10, another Th2 cytokine, nor a biallele polymorphism in the RANTES promoter affected acquisition of the SI phenotype. This finding suggested that IL-4-589T increases IL-4 production in the human body and thus accelerates the phenotypic switch of HIV-1 from NSI to SI and possibly disease progression of AIDS.

Moscatilin from Dendrobium nobile, a naturally occurring bibenzyl compound with potential antimutagenic activity.

A bibenzyl compound that possesses antimutagenic activity was isolated from the storage stem of Dendrobium nobile. The isolated compound suppressed the expression of the umu gene following the induction of SOS response in Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compound was mainly localized in the n-hexane extract fraction of the processed D. nobile. This n-hexane fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compound. EI-MS and (1)H and (13)C NMR spectroscopy were then used to delineate the structure of the compound that confers the observed antimutagenic activity. Comparison of the obtained spectrum with that found in the literature indicated that moscatilin is the secondary suppressive compound. When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, moscatilin suppressed 85% of the umu gene expression compared to the controls at <0.73 micromol/mL, with an ID(50) value of 0.41 micromol/mL. Additionally, moscatilin was tested for its ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), UV irradiation, 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), benzo[a]pyrene (B[a]P), and aflatoxin B(1) (AFB(1)). With all of the aforementioned chemicals or treatments, moscatilin showed a dramatic reduction in their mutagenic potential. Interestingly, moscatilin almost completely suppressed (97%) the AFB(1)-induced SOS response at concentrations <0.73 micromol/mL, with an ID(50) of 0.08 micromol/mL. Finally, the antimutagenic activities of moscatilin against furylfuramide and Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain. The results those experiments indicated that moscatilin demonstrated a dramatic suppression of the mutagenicity of only Trp-P-1 but not furylfuramide.

Identification of insertion mutations in HIV-1 reverse transcriptase causing multiple drug resistance to nucleoside analogue reverse transcriptase inhibitors.

OBJECTIVE: A novel 2-amino acid insertion between codons 69 and 70 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) which confers multiple drug resistance has recently been reported. Independently, we have identified similar insertion mutations in Japanese hemophiliacs and attempted to analyze their emergence in conjunction with therapy regimens and their contribution to drug resistance using recombinant technology. METHODS: The plasma and peripheral blood mononuclear cells (PBMCs) of 348 HIV-1-infected hemophiliacs were screened for HIV-1 RT mutations relevant to nucleoside analogue inhibitors and isolating viruses. Contribution of each insertion to drug resistance was studied by introducing the mutations into a T-cell line-tropic NL4-3 infectious clone and testing the drug susceptibilities of the recovered virus. RESULTS: Insertion of the 2-amino acid residue was found in 4 of the 348 cases and was strongly associated with prolonged chemotherapy with zidovudine (AZT) and didanosine (ddI). The virus isolated from 1 of the 4 cases possessed the same insertion. Characterization of these virus and the recombinant NL4-3 with the insertion strongly suggested that the insertion caused resistance not only to AZT and ddI but also to lamivudine (3TC) and zalcitabine (ddC). CONCLUSION: A 2-amino acid insertion between codons 69 and 70 of RT was detected in 4 of 348 (1.1%) Japanese hemophiliacs and was found to be associated with multiple drug resistance to nucleoside analogue RT inhibitors.

Characterization of conformation-dependent anti-gp120 murine monoclonal antibodies produced by immunization with monomeric and oligomeric human immunodeficiency virus type 1 envelope proteins.

Twenty-five conformation-dependent monoclonal antibodies (MAbs) produced by immunization of mice with oligomeric forms of the human immunodeficiency virus type 1 (HIV-1) envelope (env) glycoprotein were used to map exposed, immunogenic regions on oligomeric env. Based on MAb cross-competition, reactivity with diverse env proteins, and reactivity with a panel of gp120 mutants, seven distinct epitope clusters were identified. These include the classic CD4 binding site, V1/V2, and V3. in addition, several novel epitope clusters, including one mapping to the N- and C-termini of gp120, were identified. The locations of the seven epitope clusters on the gp120 core structure are proposed.

Isolation of azo-dye-degrading microorganisms and their application to white discharge printing of fabric.

Three bacterial strains, which degraded azo dyes, were isolated from soil and sewage samples. The strains were identified as Bacillus sp. OY1-2, Xanthomonas sp. NR25-2 and Pseudomonas sp. PR41-1. The bacteria produced azo-dyes-degrading enzymes. That catalyzed the reduction of methyl red and produced dimethyl p-phenylenediamine and o-aminobenzoic acid. The enzymes could thus be applied to white discharge printing of azo-dyed fabric by owing to there.